---
_id: '12146'
abstract:
- lang: eng
  text: 'In this paper, we explore the stability and dynamical relevance of a wide
    variety of steady, time-periodic, quasiperiodic, and chaotic flows arising between
    orthogonally stretching parallel plates. We first explore the stability of all
    the steady flow solution families formerly identified by Ayats et al. [“Flows
    between orthogonally stretching parallel plates,” Phys. Fluids 33, 024103 (2021)],
    concluding that only the one that originates from the Stokesian approximation
    is actually stable. When both plates are shrinking at identical or nearly the
    same deceleration rates, this Stokesian flow exhibits a Hopf bifurcation that
    leads to stable time-periodic regimes. The resulting time-periodic orbits or flows
    are tracked for different Reynolds numbers and stretching rates while monitoring
    their Floquet exponents to identify secondary instabilities. It is found that
    these time-periodic flows also exhibit Neimark–Sacker bifurcations, generating
    stable quasiperiodic flows (tori) that may sometimes give rise to chaotic dynamics
    through a Ruelle–Takens–Newhouse scenario. However, chaotic dynamics is unusually
    observed, as the quasiperiodic flows generally become phase-locked through a resonance
    mechanism before a strange attractor may arise, thus restoring the time-periodicity
    of the flow. In this work, we have identified and tracked four different resonance
    regions, also known as Arnold tongues or horns. In particular, the 1 : 4 strong
    resonance region is explored in great detail, where the identified scenarios are
    in very good agreement with normal form theory. '
acknowledgement: "This work was supported by the Spanish MINECO under Grant Nos. FIS2017-85794-P
  and PRX18/00179, the Spanish MICINN through Grant No. PID2020-114043GB-I00, and
  the\r\nGeneralitat de Catalunya under Grant No. 2017-SGR-785. B.W.’s research was
  also supported by the Chinese Scholarship Council through Grant CSC No. 201806440152."
article_number: '114111'
article_processing_charge: No
article_type: original
author:
- first_name: B.
  full_name: Wang, B.
  last_name: Wang
- first_name: Roger
  full_name: Ayats López, Roger
  id: ab77522d-073b-11ed-8aff-e71b39258362
  last_name: Ayats López
  orcid: 0000-0001-6572-0621
- first_name: A.
  full_name: Meseguer, A.
  last_name: Meseguer
- first_name: F.
  full_name: Marques, F.
  last_name: Marques
citation:
  ama: Wang B, Ayats López R, Meseguer A, Marques F. Phase-locking flows between orthogonally
    stretching parallel plates. <i>Physics of Fluids</i>. 2022;34(11). doi:<a href="https://doi.org/10.1063/5.0124152">10.1063/5.0124152</a>
  apa: Wang, B., Ayats López, R., Meseguer, A., &#38; Marques, F. (2022). Phase-locking
    flows between orthogonally stretching parallel plates. <i>Physics of Fluids</i>.
    AIP Publishing. <a href="https://doi.org/10.1063/5.0124152">https://doi.org/10.1063/5.0124152</a>
  chicago: Wang, B., Roger Ayats López, A. Meseguer, and F. Marques. “Phase-Locking
    Flows between Orthogonally Stretching Parallel Plates.” <i>Physics of Fluids</i>.
    AIP Publishing, 2022. <a href="https://doi.org/10.1063/5.0124152">https://doi.org/10.1063/5.0124152</a>.
  ieee: B. Wang, R. Ayats López, A. Meseguer, and F. Marques, “Phase-locking flows
    between orthogonally stretching parallel plates,” <i>Physics of Fluids</i>, vol.
    34, no. 11. AIP Publishing, 2022.
  ista: Wang B, Ayats López R, Meseguer A, Marques F. 2022. Phase-locking flows between
    orthogonally stretching parallel plates. Physics of Fluids. 34(11), 114111.
  mla: Wang, B., et al. “Phase-Locking Flows between Orthogonally Stretching Parallel
    Plates.” <i>Physics of Fluids</i>, vol. 34, no. 11, 114111, AIP Publishing, 2022,
    doi:<a href="https://doi.org/10.1063/5.0124152">10.1063/5.0124152</a>.
  short: B. Wang, R. Ayats López, A. Meseguer, F. Marques, Physics of Fluids 34 (2022).
date_created: 2023-01-12T12:06:58Z
date_published: 2022-11-04T00:00:00Z
date_updated: 2023-10-03T11:07:58Z
day: '04'
department:
- _id: BjHo
doi: 10.1063/5.0124152
external_id:
  isi:
  - '000880665300024'
intvolume: '        34'
isi: 1
issue: '11'
keyword:
- Condensed Matter Physics
- Fluid Flow and Transfer Processes
- Mechanics of Materials
- Computational Mechanics
- Mechanical Engineering
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://upcommons.upc.edu/handle/2117/385635
month: '11'
oa: 1
oa_version: Submitted Version
publication: Physics of Fluids
publication_identifier:
  eissn:
  - 1089-7666
  issn:
  - 1070-6631
publication_status: published
publisher: AIP Publishing
quality_controlled: '1'
scopus_import: '1'
status: public
title: Phase-locking flows between orthogonally stretching parallel plates
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 34
year: '2022'
...
---
_id: '12259'
abstract:
- lang: eng
  text: 'Theoretical foundations of chaos have been predominantly laid out for finite-dimensional
    dynamical systems, such as the three-body problem in classical mechanics and the
    Lorenz model in dissipative systems. In contrast, many real-world chaotic phenomena,
    e.g., weather, arise in systems with many (formally infinite) degrees of freedom,
    which limits direct quantitative analysis of such systems using chaos theory.
    In the present work, we demonstrate that the hydrodynamic pilot-wave systems offer
    a bridge between low- and high-dimensional chaotic phenomena by allowing for a
    systematic study of how the former connects to the latter. Specifically, we present
    experimental results, which show the formation of low-dimensional chaotic attractors
    upon destabilization of regular dynamics and a final transition to high-dimensional
    chaos via the merging of distinct chaotic regions through a crisis bifurcation.
    Moreover, we show that the post-crisis dynamics of the system can be rationalized
    as consecutive scatterings from the nonattracting chaotic sets with lifetimes
    following exponential distributions. '
acknowledgement: 'This work was partially funded by the Institute of Science and Technology
  Austria Interdisciplinary Project Committee Grant “Pilot-Wave Hydrodynamics: Chaos
  and Quantum Analogies.”'
article_number: '093138'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: George H
  full_name: Choueiri, George H
  id: 448BD5BC-F248-11E8-B48F-1D18A9856A87
  last_name: Choueiri
- first_name: Balachandra
  full_name: Suri, Balachandra
  id: 47A5E706-F248-11E8-B48F-1D18A9856A87
  last_name: Suri
- first_name: Jack
  full_name: Merrin, Jack
  id: 4515C308-F248-11E8-B48F-1D18A9856A87
  last_name: Merrin
  orcid: 0000-0001-5145-4609
- first_name: Maksym
  full_name: Serbyn, Maksym
  id: 47809E7E-F248-11E8-B48F-1D18A9856A87
  last_name: Serbyn
  orcid: 0000-0002-2399-5827
- first_name: Björn
  full_name: Hof, Björn
  id: 3A374330-F248-11E8-B48F-1D18A9856A87
  last_name: Hof
  orcid: 0000-0003-2057-2754
- first_name: Nazmi B
  full_name: Budanur, Nazmi B
  id: 3EA1010E-F248-11E8-B48F-1D18A9856A87
  last_name: Budanur
  orcid: 0000-0003-0423-5010
citation:
  ama: 'Choueiri GH, Suri B, Merrin J, Serbyn M, Hof B, Budanur NB. Crises and chaotic
    scattering in hydrodynamic pilot-wave experiments. <i>Chaos: An Interdisciplinary
    Journal of Nonlinear Science</i>. 2022;32(9). doi:<a href="https://doi.org/10.1063/5.0102904">10.1063/5.0102904</a>'
  apa: 'Choueiri, G. H., Suri, B., Merrin, J., Serbyn, M., Hof, B., &#38; Budanur,
    N. B. (2022). Crises and chaotic scattering in hydrodynamic pilot-wave experiments.
    <i>Chaos: An Interdisciplinary Journal of Nonlinear Science</i>. AIP Publishing.
    <a href="https://doi.org/10.1063/5.0102904">https://doi.org/10.1063/5.0102904</a>'
  chicago: 'Choueiri, George H, Balachandra Suri, Jack Merrin, Maksym Serbyn, Björn
    Hof, and Nazmi B Budanur. “Crises and Chaotic Scattering in Hydrodynamic Pilot-Wave
    Experiments.” <i>Chaos: An Interdisciplinary Journal of Nonlinear Science</i>.
    AIP Publishing, 2022. <a href="https://doi.org/10.1063/5.0102904">https://doi.org/10.1063/5.0102904</a>.'
  ieee: 'G. H. Choueiri, B. Suri, J. Merrin, M. Serbyn, B. Hof, and N. B. Budanur,
    “Crises and chaotic scattering in hydrodynamic pilot-wave experiments,” <i>Chaos:
    An Interdisciplinary Journal of Nonlinear Science</i>, vol. 32, no. 9. AIP Publishing,
    2022.'
  ista: 'Choueiri GH, Suri B, Merrin J, Serbyn M, Hof B, Budanur NB. 2022. Crises
    and chaotic scattering in hydrodynamic pilot-wave experiments. Chaos: An Interdisciplinary
    Journal of Nonlinear Science. 32(9), 093138.'
  mla: 'Choueiri, George H., et al. “Crises and Chaotic Scattering in Hydrodynamic
    Pilot-Wave Experiments.” <i>Chaos: An Interdisciplinary Journal of Nonlinear Science</i>,
    vol. 32, no. 9, 093138, AIP Publishing, 2022, doi:<a href="https://doi.org/10.1063/5.0102904">10.1063/5.0102904</a>.'
  short: 'G.H. Choueiri, B. Suri, J. Merrin, M. Serbyn, B. Hof, N.B. Budanur, Chaos:
    An Interdisciplinary Journal of Nonlinear Science 32 (2022).'
date_created: 2023-01-16T09:58:16Z
date_published: 2022-09-26T00:00:00Z
date_updated: 2023-08-04T09:51:17Z
day: '26'
ddc:
- '530'
department:
- _id: MaSe
- _id: BjHo
- _id: NanoFab
doi: 10.1063/5.0102904
external_id:
  arxiv:
  - '2206.01531'
  isi:
  - '000861009600005'
file:
- access_level: open_access
  checksum: 17881eff8b21969359a2dd64620120ba
  content_type: application/pdf
  creator: dernst
  date_created: 2023-01-30T09:41:12Z
  date_updated: 2023-01-30T09:41:12Z
  file_id: '12445'
  file_name: 2022_Chaos_Choueiri.pdf
  file_size: 3209644
  relation: main_file
  success: 1
file_date_updated: 2023-01-30T09:41:12Z
has_accepted_license: '1'
intvolume: '        32'
isi: 1
issue: '9'
keyword:
- Applied Mathematics
- General Physics and Astronomy
- Mathematical Physics
- Statistical and Nonlinear Physics
language:
- iso: eng
month: '09'
oa: 1
oa_version: Published Version
publication: 'Chaos: An Interdisciplinary Journal of Nonlinear Science'
publication_identifier:
  eissn:
  - 1089-7682
  issn:
  - 1054-1500
publication_status: published
publisher: AIP Publishing
quality_controlled: '1'
scopus_import: '1'
status: public
title: Crises and chaotic scattering in hydrodynamic pilot-wave experiments
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 32
year: '2022'
...
---
_id: '12279'
abstract:
- lang: eng
  text: We report frictional drag reduction and a complete flow relaminarization of
    elastic turbulence (ET) at vanishing inertia in a viscoelastic channel flow past
    an obstacle. We show that the intensity of the observed elastic waves and wall-normal
    vorticity correlate well with the measured drag above the onset of ET. Moreover,
    we find that the elastic wave frequency grows with the Weissenberg number, and
    at sufficiently high frequency it causes a decay of the elastic waves, resulting
    in ET attenuation and drag reduction. Thus, this allows us to substantiate a physical
    mechanism, involving the interaction of elastic waves with wall-normal vorticity
    fluctuations, leading to the drag reduction and relaminarization phenomena at
    low Reynolds number.
acknowledgement: "We thank G. Falkovich for discussion and Guy Han for technical support.
  We are grateful to N. Jha for his help in µPIV measurements. This work is partially
  supported by the grants from\r\nIsrael Science Foundation (ISF; grant #882/15 and
  grant #784/19) and Binational USA-Israel Foundation (BSF;grant #2016145). "
article_number: L081301
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: M. Vijay
  full_name: Kumar, M. Vijay
  last_name: Kumar
- first_name: Atul
  full_name: Varshney, Atul
  id: 2A2006B2-F248-11E8-B48F-1D18A9856A87
  last_name: Varshney
  orcid: 0000-0002-3072-5999
- first_name: Dongyang
  full_name: Li, Dongyang
  last_name: Li
- first_name: Victor
  full_name: Steinberg, Victor
  last_name: Steinberg
citation:
  ama: Kumar MV, Varshney A, Li D, Steinberg V. Relaminarization of elastic turbulence.
    <i>Physical Review Fluids</i>. 2022;7(8). doi:<a href="https://doi.org/10.1103/physrevfluids.7.l081301">10.1103/physrevfluids.7.l081301</a>
  apa: Kumar, M. V., Varshney, A., Li, D., &#38; Steinberg, V. (2022). Relaminarization
    of elastic turbulence. <i>Physical Review Fluids</i>. American Physical Society.
    <a href="https://doi.org/10.1103/physrevfluids.7.l081301">https://doi.org/10.1103/physrevfluids.7.l081301</a>
  chicago: Kumar, M. Vijay, Atul Varshney, Dongyang Li, and Victor Steinberg. “Relaminarization
    of Elastic Turbulence.” <i>Physical Review Fluids</i>. American Physical Society,
    2022. <a href="https://doi.org/10.1103/physrevfluids.7.l081301">https://doi.org/10.1103/physrevfluids.7.l081301</a>.
  ieee: M. V. Kumar, A. Varshney, D. Li, and V. Steinberg, “Relaminarization of elastic
    turbulence,” <i>Physical Review Fluids</i>, vol. 7, no. 8. American Physical Society,
    2022.
  ista: Kumar MV, Varshney A, Li D, Steinberg V. 2022. Relaminarization of elastic
    turbulence. Physical Review Fluids. 7(8), L081301.
  mla: Kumar, M. Vijay, et al. “Relaminarization of Elastic Turbulence.” <i>Physical
    Review Fluids</i>, vol. 7, no. 8, L081301, American Physical Society, 2022, doi:<a
    href="https://doi.org/10.1103/physrevfluids.7.l081301">10.1103/physrevfluids.7.l081301</a>.
  short: M.V. Kumar, A. Varshney, D. Li, V. Steinberg, Physical Review Fluids 7 (2022).
date_created: 2023-01-16T10:02:40Z
date_published: 2022-08-03T00:00:00Z
date_updated: 2023-08-04T10:26:40Z
day: '03'
department:
- _id: BjHo
doi: 10.1103/physrevfluids.7.l081301
external_id:
  arxiv:
  - '2205.12871'
  isi:
  - '000836397000001'
intvolume: '         7'
isi: 1
issue: '8'
keyword:
- Fluid Flow and Transfer Processes
- Modeling and Simulation
- Computational Mechanics
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: ' https://doi.org/10.48550/arXiv.2205.12871'
month: '08'
oa: 1
oa_version: Preprint
publication: Physical Review Fluids
publication_identifier:
  issn:
  - 2469-990X
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
scopus_import: '1'
status: public
title: Relaminarization of elastic turbulence
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 7
year: '2022'
...
---
_id: '8999'
abstract:
- lang: eng
  text: "In many basic shear flows, such as pipe, Couette, and channel flow, turbulence
    does not\r\narise from an instability of the laminar state, and both dynamical
    states co-exist. With decreasing flow speed (i.e., decreasing Reynolds number)
    the fraction of fluid in laminar motion increases while turbulence recedes and
    eventually the entire flow relaminarizes. The first step towards understanding
    the nature of this transition is to determine if the phase change is of either
    first or second order. In the former case, the turbulent fraction would drop discontinuously
    to zero as the Reynolds number decreases while in the latter the process would
    be continuous. For Couette flow, the flow between two parallel plates, earlier
    studies suggest a discontinuous scenario. In the present study we realize a Couette
    flow between two concentric cylinders which allows studies to be carried out in
    large aspect ratios and for extensive observation times. The presented measurements
    show that the transition in this circular Couette geometry is continuous suggesting
    that former studies were limited by finite size effects. A further characterization
    of this transition, in particular its relation to the directed percolation universality
    class, requires even larger system sizes than presently available. "
acknowledgement: "This research was funded by the Central Research Development Fund
  of the University of\r\nBremen grant number ZF04B /2019/FB04 Avila_Kerstin (“Independent
  Project for Postdocs”). Shreyas Jalikop is acknowledged for recording some of the
  lifetime measurements\r\n"
article_number: '58'
article_processing_charge: No
article_type: original
author:
- first_name: Kerstin
  full_name: Avila, Kerstin
  id: fcf74381-53e1-11eb-a6dc-b0e2acf78757
  last_name: Avila
- first_name: Björn
  full_name: Hof, Björn
  id: 3A374330-F248-11E8-B48F-1D18A9856A87
  last_name: Hof
  orcid: 0000-0003-2057-2754
citation:
  ama: Avila K, Hof B. Second-order phase transition in counter-rotating taylor-couette
    flow experiment. <i>Entropy</i>. 2021;23(1). doi:<a href="https://doi.org/10.3390/e23010058">10.3390/e23010058</a>
  apa: Avila, K., &#38; Hof, B. (2021). Second-order phase transition in counter-rotating
    taylor-couette flow experiment. <i>Entropy</i>. MDPI. <a href="https://doi.org/10.3390/e23010058">https://doi.org/10.3390/e23010058</a>
  chicago: Avila, Kerstin, and Björn Hof. “Second-Order Phase Transition in Counter-Rotating
    Taylor-Couette Flow Experiment.” <i>Entropy</i>. MDPI, 2021. <a href="https://doi.org/10.3390/e23010058">https://doi.org/10.3390/e23010058</a>.
  ieee: K. Avila and B. Hof, “Second-order phase transition in counter-rotating taylor-couette
    flow experiment,” <i>Entropy</i>, vol. 23, no. 1. MDPI, 2021.
  ista: Avila K, Hof B. 2021. Second-order phase transition in counter-rotating taylor-couette
    flow experiment. Entropy. 23(1), 58.
  mla: Avila, Kerstin, and Björn Hof. “Second-Order Phase Transition in Counter-Rotating
    Taylor-Couette Flow Experiment.” <i>Entropy</i>, vol. 23, no. 1, 58, MDPI, 2021,
    doi:<a href="https://doi.org/10.3390/e23010058">10.3390/e23010058</a>.
  short: K. Avila, B. Hof, Entropy 23 (2021).
date_created: 2021-01-10T23:01:17Z
date_published: 2021-01-01T00:00:00Z
date_updated: 2023-08-07T13:31:07Z
day: '01'
ddc:
- '530'
department:
- _id: BjHo
doi: 10.3390/e23010058
external_id:
  isi:
  - '000610135400001'
  pmid:
  - '33396499'
file:
- access_level: open_access
  checksum: 3ba3dd8b7eecff713b72c5e9ba30d626
  content_type: application/pdf
  creator: dernst
  date_created: 2021-01-11T07:50:32Z
  date_updated: 2021-01-11T07:50:32Z
  file_id: '9003'
  file_name: 2021_Entropy_Avila.pdf
  file_size: 9456389
  relation: main_file
  success: 1
file_date_updated: 2021-01-11T07:50:32Z
has_accepted_license: '1'
intvolume: '        23'
isi: 1
issue: '1'
language:
- iso: eng
month: '01'
oa: 1
oa_version: Published Version
pmid: 1
publication: Entropy
publication_identifier:
  eissn:
  - 1099-4300
publication_status: published
publisher: MDPI
quality_controlled: '1'
scopus_import: '1'
status: public
title: Second-order phase transition in counter-rotating taylor-couette flow experiment
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 23
year: '2021'
...
---
_id: '9207'
abstract:
- lang: eng
  text: "In this paper we experimentally study the transitional range of Reynolds
    numbers in\r\nplane Couette–Poiseuille flow, focusing our attention on the localized
    turbulent structures\r\ntriggered by a strong impulsive jet and the large-scale
    flow generated around these\r\nstructures. We present a detailed investigation
    of the large-scale flow and show how\r\nits amplitude depends on Reynolds number
    and amplitude perturbation. In addition,\r\nwe characterize the initial dynamics
    of the localized turbulent spot, which includes the\r\ncoupling between the small
    and large scales, as well as the dependence of the advection\r\nspeed on the large-scale
    flow generated around the spot. Finally, we provide the first\r\nexperimental
    measurements of the large-scale flow around an oblique turbulent band."
acknowledgement: "We thank Y. Duguet, S. Gomé, G. Lemoult, T. Liu, B. Semin and L.S.
  Tuckerman for\r\nfruitful discussions. \r\nThis work was supported by a grant, TRANSFLOW,
  provided by the Agence Nationale de\r\nla Recherche (ANR). A.M.P. was partially
  supported by the French Embassy in Russia (I.I. Mechnikov scholarship) and by the
  Russian Science Foundation (project no. 18-79-00189). L.K. was partially supported
  by the European Union’s Horizon 2020 research and innovation programme under the
  Marie Skłodowska-Curie grant agreement no. 754411."
article_number: A24
article_processing_charge: Yes (via OA deal)
article_type: original
author:
- first_name: Lukasz
  full_name: Klotz, Lukasz
  id: 2C9AF1C2-F248-11E8-B48F-1D18A9856A87
  last_name: Klotz
  orcid: 0000-0003-1740-7635
- first_name: A. M.
  full_name: Pavlenko, A. M.
  last_name: Pavlenko
- first_name: J. E.
  full_name: Wesfreid, J. E.
  last_name: Wesfreid
citation:
  ama: 'Klotz L, Pavlenko AM, Wesfreid JE. Experimental measurements in plane Couette-Poiseuille
    flow: Dynamics of the large- and small-scale flow. <i>Journal of Fluid Mechanics</i>.
    2021;912. doi:<a href="https://doi.org/10.1017/jfm.2020.1089">10.1017/jfm.2020.1089</a>'
  apa: 'Klotz, L., Pavlenko, A. M., &#38; Wesfreid, J. E. (2021). Experimental measurements
    in plane Couette-Poiseuille flow: Dynamics of the large- and small-scale flow.
    <i>Journal of Fluid Mechanics</i>. Cambridge University Press. <a href="https://doi.org/10.1017/jfm.2020.1089">https://doi.org/10.1017/jfm.2020.1089</a>'
  chicago: 'Klotz, Lukasz, A. M. Pavlenko, and J. E. Wesfreid. “Experimental Measurements
    in Plane Couette-Poiseuille Flow: Dynamics of the Large- and Small-Scale Flow.”
    <i>Journal of Fluid Mechanics</i>. Cambridge University Press, 2021. <a href="https://doi.org/10.1017/jfm.2020.1089">https://doi.org/10.1017/jfm.2020.1089</a>.'
  ieee: 'L. Klotz, A. M. Pavlenko, and J. E. Wesfreid, “Experimental measurements
    in plane Couette-Poiseuille flow: Dynamics of the large- and small-scale flow,”
    <i>Journal of Fluid Mechanics</i>, vol. 912. Cambridge University Press, 2021.'
  ista: 'Klotz L, Pavlenko AM, Wesfreid JE. 2021. Experimental measurements in plane
    Couette-Poiseuille flow: Dynamics of the large- and small-scale flow. Journal
    of Fluid Mechanics. 912, A24.'
  mla: 'Klotz, Lukasz, et al. “Experimental Measurements in Plane Couette-Poiseuille
    Flow: Dynamics of the Large- and Small-Scale Flow.” <i>Journal of Fluid Mechanics</i>,
    vol. 912, A24, Cambridge University Press, 2021, doi:<a href="https://doi.org/10.1017/jfm.2020.1089">10.1017/jfm.2020.1089</a>.'
  short: L. Klotz, A.M. Pavlenko, J.E. Wesfreid, Journal of Fluid Mechanics 912 (2021).
date_created: 2021-02-28T23:01:25Z
date_published: 2021-02-15T00:00:00Z
date_updated: 2023-08-07T13:55:40Z
day: '15'
ddc:
- '530'
department:
- _id: BjHo
doi: 10.1017/jfm.2020.1089
ec_funded: 1
external_id:
  isi:
  - '000618034400001'
file:
- access_level: open_access
  checksum: b8020d6338667673e34fde0608913dd2
  content_type: application/pdf
  creator: dernst
  date_created: 2021-03-03T09:49:34Z
  date_updated: 2021-03-03T09:49:34Z
  file_id: '9220'
  file_name: 2021_JourFluidMechanics_Klotz.pdf
  file_size: 4124471
  relation: main_file
  success: 1
file_date_updated: 2021-03-03T09:49:34Z
has_accepted_license: '1'
intvolume: '       912'
isi: 1
language:
- iso: eng
month: '02'
oa: 1
oa_version: Published Version
project:
- _id: 260C2330-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '754411'
  name: ISTplus - Postdoctoral Fellowships
publication: Journal of Fluid Mechanics
publication_identifier:
  eissn:
  - 1469-7645
  issn:
  - 0022-1120
publication_status: published
publisher: Cambridge University Press
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'Experimental measurements in plane Couette-Poiseuille flow: Dynamics of the
  large- and small-scale flow'
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 912
year: '2021'
...
---
_id: '9297'
abstract:
- lang: eng
  text: 'We report the results of an experimental investigation into the decay of
    turbulence in plane Couette–Poiseuille flow using ‘quench’ experiments where the
    flow laminarises after a sudden reduction in Reynolds number Re. Specifically,
    we study the velocity field in the streamwise–spanwise plane. We show that the
    spanwise velocity containing rolls decays faster than the streamwise velocity,
    which displays elongated regions of higher or lower velocity called streaks. At
    final Reynolds numbers above 425, the decay of streaks displays two stages: first
    a slow decay when rolls are present and secondly a more rapid decay of streaks
    alone. The difference in behaviour results from the regeneration of streaks by
    rolls, called the lift-up effect. We define the turbulent fraction as the portion
    of the flow containing turbulence and this is estimated by thresholding the spanwise
    velocity component. It decreases linearly with time in the whole range of final
    Re. The corresponding decay slope increases linearly with final Re. The extrapolated
    value at which this decay slope vanishes is Reaz≈656±10, close to Reg≈670 at which
    turbulence is self-sustained. The decay of the energy computed from the spanwise
    velocity component is found to be exponential. The corresponding decay rate increases
    linearly with Re, with an extrapolated vanishing value at ReAz≈688±10. This value
    is also close to the value at which the turbulence is self-sustained, showing
    that valuable information on the transition can be obtained over a wide range
    of Re.'
acknowledgement: "We gratefully acknowledge Joran Rolland, Yohann Duguet, Romain Monchaux,
  S´ebastien Gom´e, Laurette Tuckerman, Dwight Barkley, Olivier Dauchot and Sabine
  Bottin for fruitful discussions. We thank Xavier Benoit-Gonin, Amaury Fourgeaud,
  Thierry Darnige, Olivier Brouard and Justine Laurent for technical help. This work
  has benefited from the ANR TransFlow, and by starting grants obtained by B.S. from
  CNRS (INSIS) and ESPCI. T.M. was\r\nsupported by a Joliot visiting professorship
  grant from ESPCI."
article_number: A65
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: T.
  full_name: Liu, T.
  last_name: Liu
- first_name: B.
  full_name: Semin, B.
  last_name: Semin
- first_name: Lukasz
  full_name: Klotz, Lukasz
  id: 2C9AF1C2-F248-11E8-B48F-1D18A9856A87
  last_name: Klotz
  orcid: 0000-0003-1740-7635
- first_name: R.
  full_name: Godoy-Diana, R.
  last_name: Godoy-Diana
- first_name: J. E.
  full_name: Wesfreid, J. E.
  last_name: Wesfreid
- first_name: T.
  full_name: Mullin, T.
  last_name: Mullin
citation:
  ama: Liu T, Semin B, Klotz L, Godoy-Diana R, Wesfreid JE, Mullin T. Decay of streaks
    and rolls in plane Couette-Poiseuille flow. <i>Journal of Fluid Mechanics</i>.
    2021;915. doi:<a href="https://doi.org/10.1017/jfm.2021.89">10.1017/jfm.2021.89</a>
  apa: Liu, T., Semin, B., Klotz, L., Godoy-Diana, R., Wesfreid, J. E., &#38; Mullin,
    T. (2021). Decay of streaks and rolls in plane Couette-Poiseuille flow. <i>Journal
    of Fluid Mechanics</i>. Cambridge University Press. <a href="https://doi.org/10.1017/jfm.2021.89">https://doi.org/10.1017/jfm.2021.89</a>
  chicago: Liu, T., B. Semin, Lukasz Klotz, R. Godoy-Diana, J. E. Wesfreid, and T.
    Mullin. “Decay of Streaks and Rolls in Plane Couette-Poiseuille Flow.” <i>Journal
    of Fluid Mechanics</i>. Cambridge University Press, 2021. <a href="https://doi.org/10.1017/jfm.2021.89">https://doi.org/10.1017/jfm.2021.89</a>.
  ieee: T. Liu, B. Semin, L. Klotz, R. Godoy-Diana, J. E. Wesfreid, and T. Mullin,
    “Decay of streaks and rolls in plane Couette-Poiseuille flow,” <i>Journal of Fluid
    Mechanics</i>, vol. 915. Cambridge University Press, 2021.
  ista: Liu T, Semin B, Klotz L, Godoy-Diana R, Wesfreid JE, Mullin T. 2021. Decay
    of streaks and rolls in plane Couette-Poiseuille flow. Journal of Fluid Mechanics.
    915, A65.
  mla: Liu, T., et al. “Decay of Streaks and Rolls in Plane Couette-Poiseuille Flow.”
    <i>Journal of Fluid Mechanics</i>, vol. 915, A65, Cambridge University Press,
    2021, doi:<a href="https://doi.org/10.1017/jfm.2021.89">10.1017/jfm.2021.89</a>.
  short: T. Liu, B. Semin, L. Klotz, R. Godoy-Diana, J.E. Wesfreid, T. Mullin, Journal
    of Fluid Mechanics 915 (2021).
date_created: 2021-03-28T22:01:42Z
date_published: 2021-03-17T00:00:00Z
date_updated: 2023-08-07T14:30:11Z
day: '17'
department:
- _id: BjHo
doi: 10.1017/jfm.2021.89
external_id:
  arxiv:
  - '2008.08851'
  isi:
  - '000629677500001'
intvolume: '       915'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/2008.08851
month: '03'
oa: 1
oa_version: Preprint
publication: Journal of Fluid Mechanics
publication_identifier:
  eissn:
  - 1469-7645
  issn:
  - 0022-1120
publication_status: published
publisher: Cambridge University Press
quality_controlled: '1'
scopus_import: '1'
status: public
title: Decay of streaks and rolls in plane Couette-Poiseuille flow
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 915
year: '2021'
...
---
_id: '9407'
abstract:
- lang: eng
  text: 'High impact epidemics constitute one of the largest threats humanity is facing
    in the 21st century. In the absence of pharmaceutical interventions, physical
    distancing together with testing, contact tracing and quarantining are crucial
    in slowing down epidemic dynamics. Yet, here we show that if testing capacities
    are limited, containment may fail dramatically because such combined countermeasures
    drastically change the rules of the epidemic transition: Instead of continuous,
    the response to countermeasures becomes discontinuous. Rather than following the
    conventional exponential growth, the outbreak that is initially strongly suppressed
    eventually accelerates and scales faster than exponential during an explosive
    growth period. As a consequence, containment measures either suffice to stop the
    outbreak at low total case numbers or fail catastrophically if marginally too
    weak, thus implying large uncertainties in reliably estimating overall epidemic
    dynamics, both during initial phases and during second wave scenarios.'
acknowledgement: The authors thank Malte Schröder for valuable discussions and creating
  the scale-free network topologies. B.H. thanks Mukund Vasudevan for helpful discussion.
  The research by M.T. was supported by the Deutsche Forschungsgemeinschaft (DFG,
  German Research Foundation) under Germany´s Excellence Strategy–EXC-2068–390729961–Cluster
  of Excellence Physics of Life of TU Dresden.
article_number: '2586'
article_processing_charge: No
article_type: original
author:
- first_name: Davide
  full_name: Scarselli, Davide
  id: 40315C30-F248-11E8-B48F-1D18A9856A87
  last_name: Scarselli
  orcid: 0000-0001-5227-4271
- first_name: Nazmi B
  full_name: Budanur, Nazmi B
  id: 3EA1010E-F248-11E8-B48F-1D18A9856A87
  last_name: Budanur
  orcid: 0000-0003-0423-5010
- first_name: Marc
  full_name: Timme, Marc
  last_name: Timme
- first_name: Björn
  full_name: Hof, Björn
  id: 3A374330-F248-11E8-B48F-1D18A9856A87
  last_name: Hof
  orcid: 0000-0003-2057-2754
citation:
  ama: Scarselli D, Budanur NB, Timme M, Hof B. Discontinuous epidemic transition
    due to limited testing. <i>Nature Communications</i>. 2021;12(1). doi:<a href="https://doi.org/10.1038/s41467-021-22725-9">10.1038/s41467-021-22725-9</a>
  apa: Scarselli, D., Budanur, N. B., Timme, M., &#38; Hof, B. (2021). Discontinuous
    epidemic transition due to limited testing. <i>Nature Communications</i>. Springer
    Nature. <a href="https://doi.org/10.1038/s41467-021-22725-9">https://doi.org/10.1038/s41467-021-22725-9</a>
  chicago: Scarselli, Davide, Nazmi B Budanur, Marc Timme, and Björn Hof. “Discontinuous
    Epidemic Transition Due to Limited Testing.” <i>Nature Communications</i>. Springer
    Nature, 2021. <a href="https://doi.org/10.1038/s41467-021-22725-9">https://doi.org/10.1038/s41467-021-22725-9</a>.
  ieee: D. Scarselli, N. B. Budanur, M. Timme, and B. Hof, “Discontinuous epidemic
    transition due to limited testing,” <i>Nature Communications</i>, vol. 12, no.
    1. Springer Nature, 2021.
  ista: Scarselli D, Budanur NB, Timme M, Hof B. 2021. Discontinuous epidemic transition
    due to limited testing. Nature Communications. 12(1), 2586.
  mla: Scarselli, Davide, et al. “Discontinuous Epidemic Transition Due to Limited
    Testing.” <i>Nature Communications</i>, vol. 12, no. 1, 2586, Springer Nature,
    2021, doi:<a href="https://doi.org/10.1038/s41467-021-22725-9">10.1038/s41467-021-22725-9</a>.
  short: D. Scarselli, N.B. Budanur, M. Timme, B. Hof, Nature Communications 12 (2021).
date_created: 2021-05-23T22:01:42Z
date_published: 2021-05-10T00:00:00Z
date_updated: 2023-08-08T13:45:13Z
day: '10'
ddc:
- '570'
department:
- _id: BjHo
doi: 10.1038/s41467-021-22725-9
external_id:
  isi:
  - '000687305500044'
file:
- access_level: open_access
  checksum: fe26c1b8a7da1ae07a6c03f80ff06ea1
  content_type: application/pdf
  creator: kschuh
  date_created: 2021-05-25T14:18:40Z
  date_updated: 2021-05-25T14:18:40Z
  file_id: '9426'
  file_name: 2021_NatureCommunications_Scarselli.pdf
  file_size: 1176573
  relation: main_file
  success: 1
file_date_updated: 2021-05-25T14:18:40Z
has_accepted_license: '1'
intvolume: '        12'
isi: 1
issue: '1'
language:
- iso: eng
month: '05'
oa: 1
oa_version: Published Version
publication: Nature Communications
publication_identifier:
  eissn:
  - '20411723'
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
related_material:
  link:
  - description: News on IST Homepage
    relation: press_release
    url: https://ist.ac.at/en/news/smashing-the-covid-curve/
scopus_import: '1'
status: public
title: Discontinuous epidemic transition due to limited testing
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 12
year: '2021'
...
---
_id: '9467'
abstract:
- lang: eng
  text: "Turbulence in the flow of fluid through a pipe can be suppressed by buoyancy
    forces. As the suppression of turbulence leads to severe heat transfer deterioration,
    this is an important and undesirable phenomenon in both heating and cooling applications.
    Vertical flow is often considered, as the axial buoyancy force can help drive
    the flow. With heating measured by the buoyancy parameter \U0001D436, our direct
    numerical simulations show that shear-driven turbulence may either be completely
    laminarised or it transitions to a relatively quiescent convection-driven state.
    Buoyancy forces cause a flattening of the base flow profile, which in isothermal
    pipe flow has recently been linked to complete suppression of turbulence (Kühnen
    et al., Nat. Phys., vol. 14, 2018, pp. 386–390), and the flattened laminar base
    profile has enhanced nonlinear stability (Marensi et al., J. Fluid Mech., vol.
    863, 2019, pp. 50–875). In agreement with these findings, the nonlinear lower-branch
    travelling-wave solution analysed here, which is believed to mediate transition
    to turbulence in isothermal pipe flow, is shown to be suppressed by buoyancy.
    A linear instability of the laminar base flow is responsible for the appearance
    of the relatively quiescent convection driven state for \U0001D436≳4 across the
    range of Reynolds numbers considered. In the suppression of turbulence, however,
    i.e. in the transition from turbulence, we find clearer association with the analysis
    of He et al. (J. Fluid Mech., vol. 809, 2016, pp. 31–71) than with the above dynamical
    systems approach, which describes better the transition to turbulence. The laminarisation
    criterion He et al. propose, based on an apparent Reynolds number of the flow
    as measured by its driving pressure gradient, is found to capture the critical
    \U0001D436=\U0001D436\U0001D450\U0001D45F(\U0001D445\U0001D452) above which the
    flow will be laminarised or switch to the convection-driven type. Our analysis
    suggests that it is the weakened rolls, rather than the streaks, which appear
    to be critical for laminarisation."
acknowledgement: The anonymous referees are kindly acknowledged for their useful suggestions
  andcomments.
article_number: A17
article_processing_charge: Yes (via OA deal)
article_type: original
arxiv: 1
author:
- first_name: Elena
  full_name: Marensi, Elena
  id: 0BE7553A-1004-11EA-B805-18983DDC885E
  last_name: Marensi
- first_name: Shuisheng
  full_name: He, Shuisheng
  last_name: He
- first_name: Ashley P.
  full_name: Willis, Ashley P.
  last_name: Willis
citation:
  ama: Marensi E, He S, Willis AP. Suppression of turbulence and travelling waves
    in a vertical heated pipe. <i>Journal of Fluid Mechanics</i>. 2021;919. doi:<a
    href="https://doi.org/10.1017/jfm.2021.371">10.1017/jfm.2021.371</a>
  apa: Marensi, E., He, S., &#38; Willis, A. P. (2021). Suppression of turbulence
    and travelling waves in a vertical heated pipe. <i>Journal of Fluid Mechanics</i>.
    Cambridge University Press. <a href="https://doi.org/10.1017/jfm.2021.371">https://doi.org/10.1017/jfm.2021.371</a>
  chicago: Marensi, Elena, Shuisheng He, and Ashley P. Willis. “Suppression of Turbulence
    and Travelling Waves in a Vertical Heated Pipe.” <i>Journal of Fluid Mechanics</i>.
    Cambridge University Press, 2021. <a href="https://doi.org/10.1017/jfm.2021.371">https://doi.org/10.1017/jfm.2021.371</a>.
  ieee: E. Marensi, S. He, and A. P. Willis, “Suppression of turbulence and travelling
    waves in a vertical heated pipe,” <i>Journal of Fluid Mechanics</i>, vol. 919.
    Cambridge University Press, 2021.
  ista: Marensi E, He S, Willis AP. 2021. Suppression of turbulence and travelling
    waves in a vertical heated pipe. Journal of Fluid Mechanics. 919, A17.
  mla: Marensi, Elena, et al. “Suppression of Turbulence and Travelling Waves in a
    Vertical Heated Pipe.” <i>Journal of Fluid Mechanics</i>, vol. 919, A17, Cambridge
    University Press, 2021, doi:<a href="https://doi.org/10.1017/jfm.2021.371">10.1017/jfm.2021.371</a>.
  short: E. Marensi, S. He, A.P. Willis, Journal of Fluid Mechanics 919 (2021).
date_created: 2021-06-06T22:01:30Z
date_published: 2021-07-25T00:00:00Z
date_updated: 2023-08-08T13:58:41Z
day: '25'
ddc:
- '530'
department:
- _id: BjHo
doi: 10.1017/jfm.2021.371
external_id:
  arxiv:
  - '2008.13486'
  isi:
  - '000653785000001'
file:
- access_level: open_access
  checksum: 867ad077e45c181c2c5ec1311ba27c41
  content_type: application/pdf
  creator: kschuh
  date_created: 2021-08-03T09:53:28Z
  date_updated: 2021-08-03T09:53:28Z
  file_id: '9766'
  file_name: 2021_JournalFluidMechanics_Marensi.pdf
  file_size: 4087358
  relation: main_file
  success: 1
file_date_updated: 2021-08-03T09:53:28Z
has_accepted_license: '1'
intvolume: '       919'
isi: 1
language:
- iso: eng
month: '07'
oa: 1
oa_version: Published Version
publication: Journal of Fluid Mechanics
publication_identifier:
  eissn:
  - '14697645'
  issn:
  - '00221120'
publication_status: published
publisher: Cambridge University Press
quality_controlled: '1'
scopus_import: '1'
status: public
title: Suppression of turbulence and travelling waves in a vertical heated pipe
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 919
year: '2021'
...
---
_id: '9558'
abstract:
- lang: eng
  text: "We show that turbulent dynamics that arise in simulations of the three-dimensional
    Navier--Stokes equations in a triply-periodic domain under sinusoidal forcing
    can be described as transient visits to the neighborhoods of unstable time-periodic
    solutions. Based on this description, we reduce the original system with more
    than 10^5 degrees of freedom to a 17-node Markov chain where each node corresponds
    to the neighborhood of a periodic orbit. The model accurately reproduces long-term
    averages of the system's observables as weighted sums over the periodic orbits.\r\n"
acknowledged_ssus:
- _id: ScienComp
acknowledgement: "We thank the referees for improving this Letter with their comments.
  We acknowledge stimulating discussions with\r\nH. Edelsbrunner. This work was supported
  by Grant No. 662960 from the Simons Foundation (B. H.). The numerical calculations
  were performed at TUBITAK ULAKBIM High Performance and Grid Computing Center (TRUBA
  resources) and IST Austria High Performance Computing cluster."
article_number: '244502'
article_processing_charge: No
article_type: letter_note
arxiv: 1
author:
- first_name: Gökhan
  full_name: Yalniz, Gökhan
  id: 66E74FA2-D8BF-11E9-8249-8DE2E5697425
  last_name: Yalniz
  orcid: 0000-0002-8490-9312
- first_name: Björn
  full_name: Hof, Björn
  id: 3A374330-F248-11E8-B48F-1D18A9856A87
  last_name: Hof
  orcid: 0000-0003-2057-2754
- first_name: Nazmi B
  full_name: Budanur, Nazmi B
  id: 3EA1010E-F248-11E8-B48F-1D18A9856A87
  last_name: Budanur
  orcid: 0000-0003-0423-5010
citation:
  ama: Yalniz G, Hof B, Budanur NB. Coarse graining the state space of a turbulent
    flow using periodic orbits. <i>Physical Review Letters</i>. 2021;126(24). doi:<a
    href="https://doi.org/10.1103/PhysRevLett.126.244502">10.1103/PhysRevLett.126.244502</a>
  apa: Yalniz, G., Hof, B., &#38; Budanur, N. B. (2021). Coarse graining the state
    space of a turbulent flow using periodic orbits. <i>Physical Review Letters</i>.
    American Physical Society. <a href="https://doi.org/10.1103/PhysRevLett.126.244502">https://doi.org/10.1103/PhysRevLett.126.244502</a>
  chicago: Yalniz, Gökhan, Björn Hof, and Nazmi B Budanur. “Coarse Graining the State
    Space of a Turbulent Flow Using Periodic Orbits.” <i>Physical Review Letters</i>.
    American Physical Society, 2021. <a href="https://doi.org/10.1103/PhysRevLett.126.244502">https://doi.org/10.1103/PhysRevLett.126.244502</a>.
  ieee: G. Yalniz, B. Hof, and N. B. Budanur, “Coarse graining the state space of
    a turbulent flow using periodic orbits,” <i>Physical Review Letters</i>, vol.
    126, no. 24. American Physical Society, 2021.
  ista: Yalniz G, Hof B, Budanur NB. 2021. Coarse graining the state space of a turbulent
    flow using periodic orbits. Physical Review Letters. 126(24), 244502.
  mla: Yalniz, Gökhan, et al. “Coarse Graining the State Space of a Turbulent Flow
    Using Periodic Orbits.” <i>Physical Review Letters</i>, vol. 126, no. 24, 244502,
    American Physical Society, 2021, doi:<a href="https://doi.org/10.1103/PhysRevLett.126.244502">10.1103/PhysRevLett.126.244502</a>.
  short: G. Yalniz, B. Hof, N.B. Budanur, Physical Review Letters 126 (2021).
date_created: 2021-06-16T15:45:36Z
date_published: 2021-06-18T00:00:00Z
date_updated: 2023-08-08T14:08:36Z
day: '18'
department:
- _id: GradSch
- _id: BjHo
doi: 10.1103/PhysRevLett.126.244502
external_id:
  arxiv:
  - '2007.02584'
  isi:
  - '000663310100008'
intvolume: '       126'
isi: 1
issue: '24'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/2007.02584
month: '06'
oa: 1
oa_version: Preprint
project:
- _id: 238598C6-32DE-11EA-91FC-C7463DDC885E
  grant_number: '662960'
  name: 'Revisiting the Turbulence Problem Using Statistical Mechanics: Experimental
    Studies on Transitional and Turbulent Flows'
publication: Physical Review Letters
publication_identifier:
  eissn:
  - 1079-7114
  issn:
  - 0031-9007
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
related_material:
  link:
  - description: News on IST Homepage
    relation: press_release
    url: https://ist.ac.at/en/news/turbulent-flow-simplified/
status: public
title: Coarse graining the state space of a turbulent flow using periodic orbits
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 126
year: '2021'
...
---
_id: '10203'
abstract:
- lang: eng
  text: Single photon emitters in atomically-thin semiconductors can be deterministically
    positioned using strain induced by underlying nano-structures. Here, we couple
    monolayer WSe2 to high-refractive-index gallium phosphide dielectric nano-antennas
    providing both optical enhancement and monolayer deformation. For single photon
    emitters formed on such nano-antennas, we find very low (femto-Joule) saturation
    pulse energies and up to 104 times brighter photoluminescence than in WSe2 placed
    on low-refractive-index SiO2 pillars. We show that the key to these observations
    is the increase on average by a factor of 5 of the quantum efficiency of the emitters
    coupled to the nano-antennas. This further allows us to gain new insights into
    their photoluminescence dynamics, revealing the roles of the dark exciton reservoir
    and Auger processes. We also find that the coherence time of such emitters is
    limited by intrinsic dephasing processes. Our work establishes dielectric nano-antennas
    as a platform for high-efficiency quantum light generation in monolayer semiconductors.
acknowledgement: L.S., P.G.Z., and A.I.T. thank the financial support of the European
  Graphene Flagship Project under grant agreements 881603 and EPSRC grant EP/S030751/1.
  L.S. and A.I.T. thank the European Union’s Horizon 2020 research and innovation
  programme under ITN Spin-NANO Marie Sklodowska-Curie grant agreement no. 676108.
  P.G.Z. and A.I.T. thank the European Union’s Horizon 2020 research and innovation
  programme under ITN 4PHOTON Marie Sklodowska-Curie grant agreement no. 721394. J.C.,
  S.A.M., and R.S. acknowledge funding by EPSRC (EP/P033369 and EP/M013812). C.L.P.,
  A.J.B., A.I.T., and A.M.F. acknowledge funding by EPSRC Programme Grant EP/N031776/1.
  S.A.M. acknowledges the Lee-Lucas Chair in Physics, the Solar Energies go Hybrid
  (SolTech) programme, and the Deutsche Forschungsgemeinschaft (DFG, German Research
  Foundation) under Germany’s Excellence Strategy - EXC 2089/1 - 390776260.
article_number: '6063'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Luca
  full_name: Sortino, Luca
  last_name: Sortino
- first_name: Panaiot G.
  full_name: Zotev, Panaiot G.
  last_name: Zotev
- first_name: Catherine L.
  full_name: Phillips, Catherine L.
  last_name: Phillips
- first_name: Alistair J.
  full_name: Brash, Alistair J.
  last_name: Brash
- first_name: Javier
  full_name: Cambiasso, Javier
  last_name: Cambiasso
- first_name: Elena
  full_name: Marensi, Elena
  id: 0BE7553A-1004-11EA-B805-18983DDC885E
  last_name: Marensi
  orcid: 0000-0001-7173-4923
- first_name: A. Mark
  full_name: Fox, A. Mark
  last_name: Fox
- first_name: Stefan A.
  full_name: Maier, Stefan A.
  last_name: Maier
- first_name: Riccardo
  full_name: Sapienza, Riccardo
  last_name: Sapienza
- first_name: Alexander I.
  full_name: Tartakovskii, Alexander I.
  last_name: Tartakovskii
citation:
  ama: Sortino L, Zotev PG, Phillips CL, et al. Bright single photon emitters with
    enhanced quantum efficiency in a two-dimensional semiconductor coupled with dielectric
    nano-antennas. <i>Nature Communications</i>. 2021;12. doi:<a href="https://doi.org/10.1038/s41467-021-26262-3">10.1038/s41467-021-26262-3</a>
  apa: Sortino, L., Zotev, P. G., Phillips, C. L., Brash, A. J., Cambiasso, J., Marensi,
    E., … Tartakovskii, A. I. (2021). Bright single photon emitters with enhanced
    quantum efficiency in a two-dimensional semiconductor coupled with dielectric
    nano-antennas. <i>Nature Communications</i>. Springer Nature. <a href="https://doi.org/10.1038/s41467-021-26262-3">https://doi.org/10.1038/s41467-021-26262-3</a>
  chicago: Sortino, Luca, Panaiot G. Zotev, Catherine L. Phillips, Alistair J. Brash,
    Javier Cambiasso, Elena Marensi, A. Mark Fox, Stefan A. Maier, Riccardo Sapienza,
    and Alexander I. Tartakovskii. “Bright Single Photon Emitters with Enhanced Quantum
    Efficiency in a Two-Dimensional Semiconductor Coupled with Dielectric Nano-Antennas.”
    <i>Nature Communications</i>. Springer Nature, 2021. <a href="https://doi.org/10.1038/s41467-021-26262-3">https://doi.org/10.1038/s41467-021-26262-3</a>.
  ieee: L. Sortino <i>et al.</i>, “Bright single photon emitters with enhanced quantum
    efficiency in a two-dimensional semiconductor coupled with dielectric nano-antennas,”
    <i>Nature Communications</i>, vol. 12. Springer Nature, 2021.
  ista: Sortino L, Zotev PG, Phillips CL, Brash AJ, Cambiasso J, Marensi E, Fox AM,
    Maier SA, Sapienza R, Tartakovskii AI. 2021. Bright single photon emitters with
    enhanced quantum efficiency in a two-dimensional semiconductor coupled with dielectric
    nano-antennas. Nature Communications. 12, 6063.
  mla: Sortino, Luca, et al. “Bright Single Photon Emitters with Enhanced Quantum
    Efficiency in a Two-Dimensional Semiconductor Coupled with Dielectric Nano-Antennas.”
    <i>Nature Communications</i>, vol. 12, 6063, Springer Nature, 2021, doi:<a href="https://doi.org/10.1038/s41467-021-26262-3">10.1038/s41467-021-26262-3</a>.
  short: L. Sortino, P.G. Zotev, C.L. Phillips, A.J. Brash, J. Cambiasso, E. Marensi,
    A.M. Fox, S.A. Maier, R. Sapienza, A.I. Tartakovskii, Nature Communications 12
    (2021).
date_created: 2021-10-31T23:01:30Z
date_published: 2021-10-18T00:00:00Z
date_updated: 2023-08-14T08:12:12Z
day: '18'
ddc:
- '530'
department:
- _id: BjHo
doi: 10.1038/s41467-021-26262-3
external_id:
  arxiv:
  - '2103.16986'
  isi:
  - '000708601800015'
file:
- access_level: open_access
  checksum: 8580d128389860f732028c521cd5949e
  content_type: application/pdf
  creator: cchlebak
  date_created: 2021-11-03T11:31:24Z
  date_updated: 2021-11-03T11:31:24Z
  file_id: '10212'
  file_name: 2021_NatComm_Sortino.pdf
  file_size: 1434201
  relation: main_file
  success: 1
file_date_updated: 2021-11-03T11:31:24Z
has_accepted_license: '1'
intvolume: '        12'
isi: 1
language:
- iso: eng
month: '10'
oa: 1
oa_version: Published Version
publication: Nature Communications
publication_identifier:
  eissn:
  - 2041-1723
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
status: public
title: Bright single photon emitters with enhanced quantum efficiency in a two-dimensional
  semiconductor coupled with dielectric nano-antennas
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 12
year: '2021'
...
---
_id: '10299'
abstract:
- lang: eng
  text: Turbulence generally arises in shear flows if velocities and hence, inertial
    forces are sufficiently large. In striking contrast, viscoelastic fluids can exhibit
    disordered motion even at vanishing inertia. Intermediate between these cases,
    a state of chaotic motion, “elastoinertial turbulence” (EIT), has been observed
    in a narrow Reynolds number interval. We here determine the origin of EIT in experiments
    and show that characteristic EIT structures can be detected across an unexpectedly
    wide range of parameters. Close to onset, a pattern of chevron-shaped streaks
    emerges in qualitative agreement with linear and weakly nonlinear theory. However,
    in experiments, the dynamics remain weakly chaotic, and the instability can be
    traced to far lower Reynolds numbers than permitted by theory. For increasing
    inertia, the flow undergoes a transformation to a wall mode composed of inclined
    near-wall streaks and shear layers. This mode persists to what is known as the
    “maximum drag reduction limit,” and overall EIT is found to dominate viscoelastic
    flows across more than three orders of magnitude in Reynolds number.
acknowledgement: We thank Y. Dubief, R. Kerswell, E. Marensi, V. Shankar, V. Steinberg,
  and V. Terrapon for discussions and helpful comments. A.V. and B.H. acknowledge
  funding from the Austrian Science Fund, grant I4188-N30, within the Deutsche Forschungsgemeinschaft
  research unit FOR 2688.
article_number: e2102350118
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: George H
  full_name: Choueiri, George H
  id: 448BD5BC-F248-11E8-B48F-1D18A9856A87
  last_name: Choueiri
- first_name: Jose M
  full_name: Lopez Alonso, Jose M
  id: 40770848-F248-11E8-B48F-1D18A9856A87
  last_name: Lopez Alonso
  orcid: 0000-0002-0384-2022
- first_name: Atul
  full_name: Varshney, Atul
  id: 2A2006B2-F248-11E8-B48F-1D18A9856A87
  last_name: Varshney
  orcid: 0000-0002-3072-5999
- first_name: Sarath
  full_name: Sankar, Sarath
  last_name: Sankar
- first_name: Björn
  full_name: Hof, Björn
  id: 3A374330-F248-11E8-B48F-1D18A9856A87
  last_name: Hof
  orcid: 0000-0003-2057-2754
citation:
  ama: Choueiri GH, Lopez Alonso JM, Varshney A, Sankar S, Hof B. Experimental observation
    of the origin and structure of elastoinertial turbulence. <i>Proceedings of the
    National Academy of Sciences</i>. 2021;118(45). doi:<a href="https://doi.org/10.1073/pnas.2102350118">10.1073/pnas.2102350118</a>
  apa: Choueiri, G. H., Lopez Alonso, J. M., Varshney, A., Sankar, S., &#38; Hof,
    B. (2021). Experimental observation of the origin and structure of elastoinertial
    turbulence. <i>Proceedings of the National Academy of Sciences</i>. National Academy
    of Sciences. <a href="https://doi.org/10.1073/pnas.2102350118">https://doi.org/10.1073/pnas.2102350118</a>
  chicago: Choueiri, George H, Jose M Lopez Alonso, Atul Varshney, Sarath Sankar,
    and Björn Hof. “Experimental Observation of the Origin and Structure of Elastoinertial
    Turbulence.” <i>Proceedings of the National Academy of Sciences</i>. National
    Academy of Sciences, 2021. <a href="https://doi.org/10.1073/pnas.2102350118">https://doi.org/10.1073/pnas.2102350118</a>.
  ieee: G. H. Choueiri, J. M. Lopez Alonso, A. Varshney, S. Sankar, and B. Hof, “Experimental
    observation of the origin and structure of elastoinertial turbulence,” <i>Proceedings
    of the National Academy of Sciences</i>, vol. 118, no. 45. National Academy of
    Sciences, 2021.
  ista: Choueiri GH, Lopez Alonso JM, Varshney A, Sankar S, Hof B. 2021. Experimental
    observation of the origin and structure of elastoinertial turbulence. Proceedings
    of the National Academy of Sciences. 118(45), e2102350118.
  mla: Choueiri, George H., et al. “Experimental Observation of the Origin and Structure
    of Elastoinertial Turbulence.” <i>Proceedings of the National Academy of Sciences</i>,
    vol. 118, no. 45, e2102350118, National Academy of Sciences, 2021, doi:<a href="https://doi.org/10.1073/pnas.2102350118">10.1073/pnas.2102350118</a>.
  short: G.H. Choueiri, J.M. Lopez Alonso, A. Varshney, S. Sankar, B. Hof, Proceedings
    of the National Academy of Sciences 118 (2021).
date_created: 2021-11-17T13:24:24Z
date_published: 2021-11-03T00:00:00Z
date_updated: 2023-08-14T11:50:10Z
day: '03'
department:
- _id: BjHo
doi: 10.1073/pnas.2102350118
external_id:
  arxiv:
  - '2103.00023'
  isi:
  - '000720926900019'
  pmid:
  - ' 34732570'
intvolume: '       118'
isi: 1
issue: '45'
keyword:
- multidisciplinary
- elastoinertial turbulence
- viscoelastic flows
- elastic instability
- drag reduction
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/2103.00023
month: '11'
oa: 1
oa_version: Preprint
pmid: 1
project:
- _id: 238B8092-32DE-11EA-91FC-C7463DDC885E
  call_identifier: FWF
  grant_number: I04188
  name: Instabilities in pulsating pipe flow of Newtonian and complex fluids
publication: Proceedings of the National Academy of Sciences
publication_identifier:
  eissn:
  - 1091-6490
  issn:
  - 0027-8424
publication_status: published
publisher: National Academy of Sciences
quality_controlled: '1'
scopus_import: '1'
status: public
title: Experimental observation of the origin and structure of elastoinertial turbulence
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 118
year: '2021'
...
---
_id: '9728'
abstract:
- lang: eng
  text: "Most real-world flows are multiphase, yet we know little about them compared
    to their single-phase counterparts. Multiphase flows are more difficult to investigate
    as their dynamics occur in large parameter space and involve complex phenomena
    such as preferential concentration, turbulence modulation, non-Newtonian rheology,
    etc. Over the last few decades, experiments in particle-laden flows have taken
    a back seat in favour of ever-improving computational resources. However, computers
    are still not powerful enough to simulate a real-world fluid with millions of
    finite-size particles. Experiments are essential not only because they offer a
    reliable way to investigate real-world multiphase flows but also because they
    serve to validate numerical studies and steer the research in a relevant direction.
    In this work, we have experimentally investigated particle-laden flows in pipes,
    and in particular, examined the effect of particles on the laminar-turbulent transition
    and the drag scaling in turbulent flows.\r\n\r\nFor particle-laden pipe flows,
    an earlier study [Matas et al., 2003] reported how the sub-critical (i.e., hysteretic)
    transition that occurs via localised turbulent structures called puffs is affected
    by the addition of particles. In this study, in addition to this known transition,
    we found a super-critical transition to a globally fluctuating state with increasing
    particle concentration. At the same time, the Newtonian-type transition via puffs
    is delayed to larger Reynolds numbers. At an even higher concentration, only the
    globally fluctuating state is found. The dynamics of particle-laden flows are
    hence determined by two competing instabilities that give rise to three flow regimes:
    Newtonian-type turbulence at low, a particle-induced globally fluctuating state
    at high, and a coexistence state at intermediate concentrations.\r\n\r\nThe effect
    of particles on turbulent drag is ambiguous, with studies reporting drag reduction,
    no net change, and even drag increase. The ambiguity arises because, in addition
    to particle concentration, particle shape, size, and density also affect the net
    drag. Even similar particles might affect the flow dissimilarly in different Reynolds
    number and concentration ranges. In the present study, we explored a wide range
    of both Reynolds number and concentration, using spherical as well as cylindrical
    particles. We found that the spherical particles do not reduce drag while the
    cylindrical particles are drag-reducing within a specific Reynolds number interval.
    The interval strongly depends on the particle concentration and the relative size
    of the pipe and particles. Within this interval, the magnitude of drag reduction
    reaches a maximum. These drag reduction maxima appear to fall onto a distinct
    power-law curve irrespective of the pipe diameter and particle concentration,
    and this curve can be considered as the maximum drag reduction asymptote for a
    given fibre shape. Such an asymptote is well known for polymeric flows but had
    not been identified for particle-laden flows prior to this work."
acknowledged_ssus:
- _id: M-Shop
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Nishchal
  full_name: Agrawal, Nishchal
  id: 469E6004-F248-11E8-B48F-1D18A9856A87
  last_name: Agrawal
citation:
  ama: Agrawal N. Transition to turbulence and drag reduction in particle-laden pipe
    flows. 2021. doi:<a href="https://doi.org/10.15479/at:ista:9728">10.15479/at:ista:9728</a>
  apa: Agrawal, N. (2021). <i>Transition to turbulence and drag reduction in particle-laden
    pipe flows</i>. Institute of Science and Technology Austria. <a href="https://doi.org/10.15479/at:ista:9728">https://doi.org/10.15479/at:ista:9728</a>
  chicago: Agrawal, Nishchal. “Transition to Turbulence and Drag Reduction in Particle-Laden
    Pipe Flows.” Institute of Science and Technology Austria, 2021. <a href="https://doi.org/10.15479/at:ista:9728">https://doi.org/10.15479/at:ista:9728</a>.
  ieee: N. Agrawal, “Transition to turbulence and drag reduction in particle-laden
    pipe flows,” Institute of Science and Technology Austria, 2021.
  ista: Agrawal N. 2021. Transition to turbulence and drag reduction in particle-laden
    pipe flows. Institute of Science and Technology Austria.
  mla: Agrawal, Nishchal. <i>Transition to Turbulence and Drag Reduction in Particle-Laden
    Pipe Flows</i>. Institute of Science and Technology Austria, 2021, doi:<a href="https://doi.org/10.15479/at:ista:9728">10.15479/at:ista:9728</a>.
  short: N. Agrawal, Transition to Turbulence and Drag Reduction in Particle-Laden
    Pipe Flows, Institute of Science and Technology Austria, 2021.
date_created: 2021-07-27T13:40:30Z
date_published: 2021-07-29T00:00:00Z
date_updated: 2024-02-28T13:14:39Z
day: '29'
ddc:
- '532'
degree_awarded: PhD
department:
- _id: GradSch
- _id: BjHo
doi: 10.15479/at:ista:9728
file:
- access_level: closed
  checksum: 77436be3563a90435024307b1b5ee7e8
  content_type: application/x-zip-compressed
  creator: nagrawal
  date_created: 2021-07-28T13:32:02Z
  date_updated: 2022-07-29T22:30:05Z
  embargo_to: open_access
  file_id: '9744'
  file_name: Transition to Turbulence and Drag Reduction in Particle-Laden Pipe Flows.zip
  file_size: 22859658
  relation: source_file
- access_level: open_access
  checksum: 72a891d7daba85445c29b868c22575ed
  content_type: application/pdf
  creator: nagrawal
  date_created: 2021-07-28T13:32:05Z
  date_updated: 2022-07-29T22:30:05Z
  embargo: 2022-07-28
  file_id: '9745'
  file_name: Transition to Turbulence and Drag Reduction in Particle-Laden Pipe Flows.pdf
  file_size: 18658048
  relation: main_file
file_date_updated: 2022-07-29T22:30:05Z
has_accepted_license: '1'
keyword:
- Drag Reduction
- Transition to Turbulence
- Multiphase Flows
- particle Laden Flows
- Complex Flows
- Experiments
- Fluid Dynamics
language:
- iso: eng
month: '07'
oa: 1
oa_version: Published Version
page: '118'
publication_identifier:
  issn:
  - 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
  record:
  - id: '6189'
    relation: part_of_dissertation
    status: public
status: public
supervisor:
- first_name: Björn
  full_name: Hof, Björn
  id: 3A374330-F248-11E8-B48F-1D18A9856A87
  last_name: Hof
  orcid: 0000-0003-2057-2754
title: Transition to turbulence and drag reduction in particle-laden pipe flows
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: dissertation
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
year: '2021'
...
---
_id: '7932'
abstract:
- lang: eng
  text: Pulsating flows through tubular geometries are laminar provided that velocities
    are moderate. This in particular is also believed to apply to cardiovascular flows
    where inertial forces are typically too low to sustain turbulence. On the other
    hand, flow instabilities and fluctuating shear stresses are held responsible for
    a variety of cardiovascular diseases. Here we report a nonlinear instability mechanism
    for pulsating pipe flow that gives rise to bursts of turbulence at low flow rates.
    Geometrical distortions of small, yet finite, amplitude are found to excite a
    state consisting of helical vortices during flow deceleration. The resulting flow
    pattern grows rapidly in magnitude, breaks down into turbulence, and eventually
    returns to laminar when the flow accelerates. This scenario causes shear stress
    fluctuations and flow reversal during each pulsation cycle. Such unsteady conditions
    can adversely affect blood vessels and have been shown to promote inflammation
    and dysfunction of the shear stress-sensitive endothelial cell layer.
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Duo
  full_name: Xu, Duo
  id: 3454D55E-F248-11E8-B48F-1D18A9856A87
  last_name: Xu
- first_name: Atul
  full_name: Varshney, Atul
  id: 2A2006B2-F248-11E8-B48F-1D18A9856A87
  last_name: Varshney
  orcid: 0000-0002-3072-5999
- first_name: Xingyu
  full_name: Ma, Xingyu
  id: 34BADBA6-F248-11E8-B48F-1D18A9856A87
  last_name: Ma
  orcid: 0000-0002-0179-9737
- first_name: Baofang
  full_name: Song, Baofang
  last_name: Song
- first_name: Michael
  full_name: Riedl, Michael
  id: 3BE60946-F248-11E8-B48F-1D18A9856A87
  last_name: Riedl
  orcid: 0000-0003-4844-6311
- first_name: Marc
  full_name: Avila, Marc
  last_name: Avila
- first_name: Björn
  full_name: Hof, Björn
  id: 3A374330-F248-11E8-B48F-1D18A9856A87
  last_name: Hof
  orcid: 0000-0003-2057-2754
citation:
  ama: Xu D, Varshney A, Ma X, et al. Nonlinear hydrodynamic instability and turbulence
    in pulsatile flow. <i>Proceedings of the National Academy of Sciences of the United
    States of America</i>. 2020;117(21):11233-11239. doi:<a href="https://doi.org/10.1073/pnas.1913716117">10.1073/pnas.1913716117</a>
  apa: Xu, D., Varshney, A., Ma, X., Song, B., Riedl, M., Avila, M., &#38; Hof, B.
    (2020). Nonlinear hydrodynamic instability and turbulence in pulsatile flow. <i>Proceedings
    of the National Academy of Sciences of the United States of America</i>. National
    Academy of Sciences. <a href="https://doi.org/10.1073/pnas.1913716117">https://doi.org/10.1073/pnas.1913716117</a>
  chicago: Xu, Duo, Atul Varshney, Xingyu Ma, Baofang Song, Michael Riedl, Marc Avila,
    and Björn Hof. “Nonlinear Hydrodynamic Instability and Turbulence in Pulsatile
    Flow.” <i>Proceedings of the National Academy of Sciences of the United States
    of America</i>. National Academy of Sciences, 2020. <a href="https://doi.org/10.1073/pnas.1913716117">https://doi.org/10.1073/pnas.1913716117</a>.
  ieee: D. Xu <i>et al.</i>, “Nonlinear hydrodynamic instability and turbulence in
    pulsatile flow,” <i>Proceedings of the National Academy of Sciences of the United
    States of America</i>, vol. 117, no. 21. National Academy of Sciences, pp. 11233–11239,
    2020.
  ista: Xu D, Varshney A, Ma X, Song B, Riedl M, Avila M, Hof B. 2020. Nonlinear hydrodynamic
    instability and turbulence in pulsatile flow. Proceedings of the National Academy
    of Sciences of the United States of America. 117(21), 11233–11239.
  mla: Xu, Duo, et al. “Nonlinear Hydrodynamic Instability and Turbulence in Pulsatile
    Flow.” <i>Proceedings of the National Academy of Sciences of the United States
    of America</i>, vol. 117, no. 21, National Academy of Sciences, 2020, pp. 11233–39,
    doi:<a href="https://doi.org/10.1073/pnas.1913716117">10.1073/pnas.1913716117</a>.
  short: D. Xu, A. Varshney, X. Ma, B. Song, M. Riedl, M. Avila, B. Hof, Proceedings
    of the National Academy of Sciences of the United States of America 117 (2020)
    11233–11239.
date_created: 2020-06-07T22:00:51Z
date_published: 2020-05-26T00:00:00Z
date_updated: 2023-11-30T10:55:13Z
day: '26'
department:
- _id: BjHo
doi: 10.1073/pnas.1913716117
ec_funded: 1
external_id:
  arxiv:
  - '2005.11190'
  isi:
  - '000536797100014'
intvolume: '       117'
isi: 1
issue: '21'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/2005.11190
month: '05'
oa: 1
oa_version: Preprint
page: 11233-11239
project:
- _id: 238B8092-32DE-11EA-91FC-C7463DDC885E
  call_identifier: FWF
  grant_number: I04188
  name: Instabilities in pulsating pipe flow of Newtonian and complex fluids
- _id: 260C2330-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '754411'
  name: ISTplus - Postdoctoral Fellowships
publication: Proceedings of the National Academy of Sciences of the United States
  of America
publication_identifier:
  eissn:
  - '10916490'
  issn:
  - '00278424'
publication_status: published
publisher: National Academy of Sciences
quality_controlled: '1'
related_material:
  link:
  - description: News on IST Homepage
    relation: press_release
    url: https://ist.ac.at/en/news/blood-flows-more-turbulent-than-previously-expected/
  record:
  - id: '12726'
    relation: dissertation_contains
    status: public
  - id: '14530'
    relation: dissertation_contains
    status: public
scopus_import: '1'
status: public
title: Nonlinear hydrodynamic instability and turbulence in pulsatile flow
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 117
year: '2020'
...
---
_id: '8043'
abstract:
- lang: eng
  text: With decreasing Reynolds number, Re, turbulence in channel flow becomes spatio-temporally
    intermittent and self-organises into solitary stripes oblique to the mean flow
    direction. We report here the existence of localised nonlinear travelling wave
    solutions of the Navier–Stokes equations possessing this obliqueness property.
    Such solutions are identified numerically using edge tracking coupled with arclength
    continuation. All solutions emerge in saddle-node bifurcations at values of Re
    lower than the non-localised solutions. Relative periodic orbit solutions bifurcating
    from branches of travelling waves have also been computed. A complete parametric
    study is performed, including their stability, the investigation of their large-scale
    flow, and the robustness to changes of the numerical domain.
acknowledgement: The authors thank S. Zammert and B. Budanur for useful discussions.
  J. F. Gibson is gratefully acknowledged for the development and the maintenance
  of the code Channelflow. Y.D. would like to thank P. Schlatter and D. S. Henningson
  for an early collaboration on a similar topic in the case of plane Couette flow
  during the years 2008–2013.
article_number: A7
article_processing_charge: Yes (via OA deal)
article_type: original
author:
- first_name: Chaitanya S
  full_name: Paranjape, Chaitanya S
  id: 3D85B7C4-F248-11E8-B48F-1D18A9856A87
  last_name: Paranjape
- first_name: Yohann
  full_name: Duguet, Yohann
  last_name: Duguet
- first_name: Björn
  full_name: Hof, Björn
  id: 3A374330-F248-11E8-B48F-1D18A9856A87
  last_name: Hof
  orcid: 0000-0003-2057-2754
citation:
  ama: Paranjape CS, Duguet Y, Hof B. Oblique stripe solutions of channel flow. <i>Journal
    of Fluid Mechanics</i>. 2020;897. doi:<a href="https://doi.org/10.1017/jfm.2020.322">10.1017/jfm.2020.322</a>
  apa: Paranjape, C. S., Duguet, Y., &#38; Hof, B. (2020). Oblique stripe solutions
    of channel flow. <i>Journal of Fluid Mechanics</i>. Cambridge University Press.
    <a href="https://doi.org/10.1017/jfm.2020.322">https://doi.org/10.1017/jfm.2020.322</a>
  chicago: Paranjape, Chaitanya S, Yohann Duguet, and Björn Hof. “Oblique Stripe Solutions
    of Channel Flow.” <i>Journal of Fluid Mechanics</i>. Cambridge University Press,
    2020. <a href="https://doi.org/10.1017/jfm.2020.322">https://doi.org/10.1017/jfm.2020.322</a>.
  ieee: C. S. Paranjape, Y. Duguet, and B. Hof, “Oblique stripe solutions of channel
    flow,” <i>Journal of Fluid Mechanics</i>, vol. 897. Cambridge University Press,
    2020.
  ista: Paranjape CS, Duguet Y, Hof B. 2020. Oblique stripe solutions of channel flow.
    Journal of Fluid Mechanics. 897, A7.
  mla: Paranjape, Chaitanya S., et al. “Oblique Stripe Solutions of Channel Flow.”
    <i>Journal of Fluid Mechanics</i>, vol. 897, A7, Cambridge University Press, 2020,
    doi:<a href="https://doi.org/10.1017/jfm.2020.322">10.1017/jfm.2020.322</a>.
  short: C.S. Paranjape, Y. Duguet, B. Hof, Journal of Fluid Mechanics 897 (2020).
date_created: 2020-06-29T07:59:35Z
date_published: 2020-08-25T00:00:00Z
date_updated: 2023-08-22T07:48:02Z
day: '25'
ddc:
- '530'
department:
- _id: BjHo
doi: 10.1017/jfm.2020.322
external_id:
  isi:
  - '000539132300001'
file:
- access_level: open_access
  checksum: 3f487bf6d9286787096306eaa18702e8
  content_type: application/pdf
  creator: cziletti
  date_created: 2020-06-30T08:37:37Z
  date_updated: 2020-07-14T12:48:08Z
  file_id: '8070'
  file_name: 2020_JournalOfFluidMech_Paranjape.pdf
  file_size: 767873
  relation: main_file
file_date_updated: 2020-07-14T12:48:08Z
has_accepted_license: '1'
intvolume: '       897'
isi: 1
language:
- iso: eng
month: '08'
oa: 1
oa_version: Published Version
publication: Journal of Fluid Mechanics
publication_identifier:
  eissn:
  - '14697645'
  issn:
  - '00221120'
publication_status: published
publisher: Cambridge University Press
quality_controlled: '1'
scopus_import: '1'
status: public
title: Oblique stripe solutions of channel flow
tmp:
  image: /images/cc_by_nc_sa.png
  legal_code_url: https://creativecommons.org/licenses/by-nc-sa/4.0/legalcode
  name: Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC
    BY-NC-SA 4.0)
  short: CC BY-NC-SA (4.0)
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 897
year: '2020'
...
---
_id: '8350'
abstract:
- lang: eng
  text: "Cytoplasm is a gel-like crowded environment composed of tens of thousands
    of macromolecules, organelles, cytoskeletal networks and cytosol. The structure
    of the cytoplasm is thought to be highly organized and heterogeneous due to the
    crowding of its constituents and their effective compartmentalization. In such
    an environment, the diffusive dynamics of the molecules is very restricted, an
    effect that is further amplified by clustering and anchoring of molecules. Despite
    the jammed nature of the cytoplasm at the microscopic scale, large-scale reorganization
    of cytoplasm is essential for important cellular functions, such as nuclear positioning
    and cell division. How such mesoscale reorganization of the cytoplasm is achieved,
    especially for very large cells such as oocytes or syncytial tissues that can
    span hundreds of micrometers in size, has only begun to be understood.\r\nIn this
    thesis, I focus on the recent advances in elucidating the molecular, cellular
    and biophysical principles underlying cytoplasmic organization across different
    scales, structures and species. First, I outline which of these principles have
    been identified by reductionist approaches, such as in vitro reconstitution assays,
    where boundary conditions and components can be modulated at ease. I then describe
    how the theoretical and experimental framework established in these reduced systems
    have been applied to their more complex in vivo counterparts, in particular oocytes
    and embryonic syncytial structures, and discuss how such complex biological systems
    can initiate symmetry breaking and establish patterning.\r\nSpecifically, I examine
    an example of large-scale reorganizations taking place in zebrafish embryos, where
    extensive cytoplasmic streaming leads to the segregation of cytoplasm from yolk
    granules along the animal-vegetal axis of the embryo. Using biophysical experimentation
    and theory, I investigate the forces underlying this process, to show that this
    process does not rely on cortical actin reorganization, as previously thought,
    but instead on a cell-cycle-dependent bulk actin polymerization wave traveling
    from the animal to the vegetal pole of the embryo. This wave functions in segregation
    by both pulling cytoplasm animally and pushing yolk granules vegetally. Cytoplasm
    pulling is mediated by bulk actin network flows exerting friction forces on the
    cytoplasm, while yolk granule pushing is achieved by a mechanism closely resembling
    actin comet formation on yolk granules. This study defines a novel role of bulk
    actin polymerization waves in embryo polarization via cytoplasmic segregation.
    Lastly, I describe the cytoplasmic reorganizations taking place during zebrafish
    oocyte maturation, where the initial segregation of the cytoplasm and yolk granules
    occurs. Here, I demonstrate a previously uncharacterized wave of microtubule aster
    formation, traveling the oocyte along the animal-vegetal axis. Further research
    is required to determine the role of such microtubule structures in cytoplasmic
    reorganizations therein.\r\nCollectively, these studies provide further evidence
    for the coupling between cell cytoskeleton and cell cycle machinery, which can
    underlie a core self-organizing mechanism for orchestrating large-scale reorganizations
    in a cell-cycle-tunable manner, where the modulations of the force-generating
    machinery and cytoplasmic mechanics can be harbored to fulfill cellular functions."
acknowledged_ssus:
- _id: PreCl
- _id: Bio
- _id: EM-Fac
acknowledgement: "I would have had no fish and hence no results without our wonderful
  fish facility crew, Verena Mayer, Eva Schlegl, Andreas Mlak and Matthias Nowak.
  Special thanks to Verena for being always happy to help and dealing with our chaotic
  schedules in the lab. Danke auch, Verena, für deine Geduld, mit mir auf Deutsch
  zu sprechen. Das hat mir sehr geholfen.\r\nSpecial thanks to the Bioimaging and
  EM facilities at IST Austria for supporting us every day. Very special thanks would
  go to Robert Hauschild for his continuous support on data analysis and also to Jack
  Merrin for designing and building microfabricated chambers for the project and for
  the various discussions on making zebrafish extracts."
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Shayan
  full_name: Shamipour, Shayan
  id: 40B34FE2-F248-11E8-B48F-1D18A9856A87
  last_name: Shamipour
citation:
  ama: Shamipour S. Bulk actin dynamics drive phase segregation in zebrafish oocytes
    . 2020. doi:<a href="https://doi.org/10.15479/AT:ISTA:8350">10.15479/AT:ISTA:8350</a>
  apa: Shamipour, S. (2020). <i>Bulk actin dynamics drive phase segregation in zebrafish
    oocytes </i>. Institute of Science and Technology Austria. <a href="https://doi.org/10.15479/AT:ISTA:8350">https://doi.org/10.15479/AT:ISTA:8350</a>
  chicago: Shamipour, Shayan. “Bulk Actin Dynamics Drive Phase Segregation in Zebrafish
    Oocytes .” Institute of Science and Technology Austria, 2020. <a href="https://doi.org/10.15479/AT:ISTA:8350">https://doi.org/10.15479/AT:ISTA:8350</a>.
  ieee: S. Shamipour, “Bulk actin dynamics drive phase segregation in zebrafish oocytes
    ,” Institute of Science and Technology Austria, 2020.
  ista: Shamipour S. 2020. Bulk actin dynamics drive phase segregation in zebrafish
    oocytes . Institute of Science and Technology Austria.
  mla: Shamipour, Shayan. <i>Bulk Actin Dynamics Drive Phase Segregation in Zebrafish
    Oocytes </i>. Institute of Science and Technology Austria, 2020, doi:<a href="https://doi.org/10.15479/AT:ISTA:8350">10.15479/AT:ISTA:8350</a>.
  short: S. Shamipour, Bulk Actin Dynamics Drive Phase Segregation in Zebrafish Oocytes
    , Institute of Science and Technology Austria, 2020.
date_created: 2020-09-09T11:12:10Z
date_published: 2020-09-09T00:00:00Z
date_updated: 2023-09-27T14:16:45Z
day: '09'
ddc:
- '570'
degree_awarded: PhD
department:
- _id: BjHo
- _id: CaHe
doi: 10.15479/AT:ISTA:8350
file:
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  checksum: 6e47871c74f85008b9876112eb3fcfa1
  content_type: application/vnd.openxmlformats-officedocument.wordprocessingml.document
  creator: sshamip
  date_created: 2020-09-09T11:06:27Z
  date_updated: 2021-09-11T22:30:05Z
  embargo_to: open_access
  file_id: '8351'
  file_name: Shayan-Thesis-Final.docx
  file_size: 65194814
  relation: source_file
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  content_type: application/pdf
  creator: sshamip
  date_created: 2020-09-09T11:06:13Z
  date_updated: 2021-09-11T22:30:05Z
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file_date_updated: 2021-09-11T22:30:05Z
has_accepted_license: '1'
language:
- iso: eng
month: '09'
oa: 1
oa_version: None
page: '107'
publication_identifier:
  issn:
  - 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
  record:
  - id: '661'
    relation: part_of_dissertation
    status: public
  - id: '6508'
    relation: part_of_dissertation
    status: public
  - id: '7001'
    relation: part_of_dissertation
    status: public
  - id: '735'
    relation: part_of_dissertation
    status: public
status: public
supervisor:
- first_name: Carl-Philipp J
  full_name: Heisenberg, Carl-Philipp J
  id: 39427864-F248-11E8-B48F-1D18A9856A87
  last_name: Heisenberg
  orcid: 0000-0002-0912-4566
- first_name: Björn
  full_name: Hof, Björn
  id: 3A374330-F248-11E8-B48F-1D18A9856A87
  last_name: Hof
  orcid: 0000-0003-2057-2754
title: 'Bulk actin dynamics drive phase segregation in zebrafish oocytes '
type: dissertation
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
year: '2020'
...
---
_id: '8634'
abstract:
- lang: eng
  text: In laboratory studies and numerical simulations, we observe clear signatures
    of unstable time-periodic solutions in a moderately turbulent quasi-two-dimensional
    flow. We validate the dynamical relevance of such solutions by demonstrating that
    turbulent flows in both experiment and numerics transiently display time-periodic
    dynamics when they shadow unstable periodic orbits (UPOs). We show that UPOs we
    computed are also statistically significant, with turbulent flows spending a sizable
    fraction of the total time near these solutions. As a result, the average rates
    of energy input and dissipation for the turbulent flow and frequently visited
    UPOs differ only by a few percent.
acknowledgement: M. F. S. and R. O. G. acknowledge funding from the National Science
  Foundation (CMMI-1234436, DMS1125302, CMMI-1725587) and Defense Advanced Research
  Projects Agency (HR0011-16-2-0033). B. S.has received funding from the People Programme
  (Marie Curie Actions) of the European Union's Seventh Framework Programme FP7/2007–2013/
  under REA Grant Agreement No. 291734.
article_number: '064501'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Balachandra
  full_name: Suri, Balachandra
  id: 47A5E706-F248-11E8-B48F-1D18A9856A87
  last_name: Suri
- first_name: Logan
  full_name: Kageorge, Logan
  last_name: Kageorge
- first_name: Roman O.
  full_name: Grigoriev, Roman O.
  last_name: Grigoriev
- first_name: Michael F.
  full_name: Schatz, Michael F.
  last_name: Schatz
citation:
  ama: Suri B, Kageorge L, Grigoriev RO, Schatz MF. Capturing turbulent dynamics and
    statistics in experiments with unstable periodic orbits. <i>Physical Review Letters</i>.
    2020;125(6). doi:<a href="https://doi.org/10.1103/physrevlett.125.064501">10.1103/physrevlett.125.064501</a>
  apa: Suri, B., Kageorge, L., Grigoriev, R. O., &#38; Schatz, M. F. (2020). Capturing
    turbulent dynamics and statistics in experiments with unstable periodic orbits.
    <i>Physical Review Letters</i>. American Physical Society. <a href="https://doi.org/10.1103/physrevlett.125.064501">https://doi.org/10.1103/physrevlett.125.064501</a>
  chicago: Suri, Balachandra, Logan Kageorge, Roman O. Grigoriev, and Michael F. Schatz.
    “Capturing Turbulent Dynamics and Statistics in Experiments with Unstable Periodic
    Orbits.” <i>Physical Review Letters</i>. American Physical Society, 2020. <a href="https://doi.org/10.1103/physrevlett.125.064501">https://doi.org/10.1103/physrevlett.125.064501</a>.
  ieee: B. Suri, L. Kageorge, R. O. Grigoriev, and M. F. Schatz, “Capturing turbulent
    dynamics and statistics in experiments with unstable periodic orbits,” <i>Physical
    Review Letters</i>, vol. 125, no. 6. American Physical Society, 2020.
  ista: Suri B, Kageorge L, Grigoriev RO, Schatz MF. 2020. Capturing turbulent dynamics
    and statistics in experiments with unstable periodic orbits. Physical Review Letters.
    125(6), 064501.
  mla: Suri, Balachandra, et al. “Capturing Turbulent Dynamics and Statistics in Experiments
    with Unstable Periodic Orbits.” <i>Physical Review Letters</i>, vol. 125, no.
    6, 064501, American Physical Society, 2020, doi:<a href="https://doi.org/10.1103/physrevlett.125.064501">10.1103/physrevlett.125.064501</a>.
  short: B. Suri, L. Kageorge, R.O. Grigoriev, M.F. Schatz, Physical Review Letters
    125 (2020).
date_created: 2020-10-08T17:27:32Z
date_published: 2020-08-05T00:00:00Z
date_updated: 2023-09-05T12:08:29Z
day: '05'
department:
- _id: BjHo
doi: 10.1103/physrevlett.125.064501
ec_funded: 1
external_id:
  arxiv:
  - '2008.02367'
  isi:
  - '000555785600005'
intvolume: '       125'
isi: 1
issue: '6'
keyword:
- General Physics and Astronomy
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/2008.02367
month: '08'
oa: 1
oa_version: Preprint
project:
- _id: 25681D80-B435-11E9-9278-68D0E5697425
  call_identifier: FP7
  grant_number: '291734'
  name: International IST Postdoc Fellowship Programme
publication: Physical Review Letters
publication_identifier:
  eissn:
  - 1079-7114
  issn:
  - 0031-9007
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
status: public
title: Capturing turbulent dynamics and statistics in experiments with unstable periodic
  orbits
type: journal_article
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 125
year: '2020'
...
---
_id: '7258'
abstract:
- lang: eng
  text: Many flows encountered in nature and applications are characterized by a chaotic
    motion known as turbulence. Turbulent flows generate intense friction with pipe
    walls and are responsible for considerable amounts of energy losses at world scale.
    The nature of turbulent friction and techniques aimed at reducing it have been
    subject of extensive research over the last century, but no definite answer has
    been found yet. In this thesis we show that in pipes at moderate turbulent Reynolds
    numbers friction is better described by the power law first introduced by Blasius
    and not by the Prandtl–von Kármán formula. At higher Reynolds numbers, large scale
    motions gradually become more important in the flow and can be related to the
    change in scaling of friction. Next, we present a series of new techniques that
    can relaminarize turbulence by suppressing a key mechanism that regenerates it
    at walls, the lift–up effect. In addition, we investigate the process of turbulence
    decay in several experiments and discuss the drag reduction potential. Finally,
    we examine the behavior of friction under pulsating conditions inspired by the
    human heart cycle and we show that under such circumstances turbulent friction
    can be reduced to produce energy savings.
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Davide
  full_name: Scarselli, Davide
  id: 40315C30-F248-11E8-B48F-1D18A9856A87
  last_name: Scarselli
  orcid: 0000-0001-5227-4271
citation:
  ama: Scarselli D. New approaches to reduce friction in turbulent pipe flow. 2020.
    doi:<a href="https://doi.org/10.15479/AT:ISTA:7258">10.15479/AT:ISTA:7258</a>
  apa: Scarselli, D. (2020). <i>New approaches to reduce friction in turbulent pipe
    flow</i>. Institute of Science and Technology Austria. <a href="https://doi.org/10.15479/AT:ISTA:7258">https://doi.org/10.15479/AT:ISTA:7258</a>
  chicago: Scarselli, Davide. “New Approaches to Reduce Friction in Turbulent Pipe
    Flow.” Institute of Science and Technology Austria, 2020. <a href="https://doi.org/10.15479/AT:ISTA:7258">https://doi.org/10.15479/AT:ISTA:7258</a>.
  ieee: D. Scarselli, “New approaches to reduce friction in turbulent pipe flow,”
    Institute of Science and Technology Austria, 2020.
  ista: Scarselli D. 2020. New approaches to reduce friction in turbulent pipe flow.
    Institute of Science and Technology Austria.
  mla: Scarselli, Davide. <i>New Approaches to Reduce Friction in Turbulent Pipe Flow</i>.
    Institute of Science and Technology Austria, 2020, doi:<a href="https://doi.org/10.15479/AT:ISTA:7258">10.15479/AT:ISTA:7258</a>.
  short: D. Scarselli, New Approaches to Reduce Friction in Turbulent Pipe Flow, Institute
    of Science and Technology Austria, 2020.
date_created: 2020-01-12T16:07:26Z
date_published: 2020-01-13T00:00:00Z
date_updated: 2023-09-15T12:20:08Z
day: '13'
ddc:
- '532'
degree_awarded: PhD
department:
- _id: BjHo
doi: 10.15479/AT:ISTA:7258
ec_funded: 1
file:
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has_accepted_license: '1'
language:
- iso: eng
month: '01'
oa: 1
oa_version: None
page: '174'
project:
- _id: 25152F3A-B435-11E9-9278-68D0E5697425
  call_identifier: FP7
  grant_number: '306589'
  name: Decoding the complexity of turbulence at its origin
- _id: 25104D44-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '737549'
  name: Eliminating turbulence in oil pipelines
- _id: 25136C54-B435-11E9-9278-68D0E5697425
  grant_number: HO 4393/1-2
  name: Experimental studies of the turbulence transition and transport processes
    in turbulent Taylor-Couette currents
publication_identifier:
  issn:
  - 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
  record:
  - id: '6228'
    relation: part_of_dissertation
    status: public
  - id: '6486'
    relation: part_of_dissertation
    status: public
  - id: '461'
    relation: part_of_dissertation
    status: public
  - id: '422'
    relation: part_of_dissertation
    status: public
status: public
supervisor:
- first_name: Björn
  full_name: Hof, Björn
  id: 3A374330-F248-11E8-B48F-1D18A9856A87
  last_name: Hof
  orcid: 0000-0003-2057-2754
title: New approaches to reduce friction in turbulent pipe flow
type: dissertation
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
year: '2020'
...
---
_id: '7364'
abstract:
- lang: eng
  text: We present nsCouette, a highly scalable software tool to solve the Navier–Stokes
    equations for incompressible fluid flow between differentially heated and independently
    rotating, concentric cylinders. It is based on a pseudospectral spatial discretization
    and dynamic time-stepping. It is implemented in modern Fortran with a hybrid MPI-OpenMP
    parallelization scheme and thus designed to compute turbulent flows at high Reynolds
    and Rayleigh numbers. An additional GPU implementation (C-CUDA) for intermediate
    problem sizes and a version for pipe flow (nsPipe) are also provided.
article_number: '100395'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Jose M
  full_name: Lopez Alonso, Jose M
  id: 40770848-F248-11E8-B48F-1D18A9856A87
  last_name: Lopez Alonso
  orcid: 0000-0002-0384-2022
- first_name: Daniel
  full_name: Feldmann, Daniel
  last_name: Feldmann
- first_name: Markus
  full_name: Rampp, Markus
  last_name: Rampp
- first_name: Alberto
  full_name: Vela-Martín, Alberto
  last_name: Vela-Martín
- first_name: Liang
  full_name: Shi, Liang
  id: 374A3F1A-F248-11E8-B48F-1D18A9856A87
  last_name: Shi
- first_name: Marc
  full_name: Avila, Marc
  last_name: Avila
citation:
  ama: Lopez Alonso JM, Feldmann D, Rampp M, Vela-Martín A, Shi L, Avila M. nsCouette
    – A high-performance code for direct numerical simulations of turbulent Taylor–Couette
    flow. <i>SoftwareX</i>. 2020;11. doi:<a href="https://doi.org/10.1016/j.softx.2019.100395">10.1016/j.softx.2019.100395</a>
  apa: Lopez Alonso, J. M., Feldmann, D., Rampp, M., Vela-Martín, A., Shi, L., &#38;
    Avila, M. (2020). nsCouette – A high-performance code for direct numerical simulations
    of turbulent Taylor–Couette flow. <i>SoftwareX</i>. Elsevier. <a href="https://doi.org/10.1016/j.softx.2019.100395">https://doi.org/10.1016/j.softx.2019.100395</a>
  chicago: Lopez Alonso, Jose M, Daniel Feldmann, Markus Rampp, Alberto Vela-Martín,
    Liang Shi, and Marc Avila. “NsCouette – A High-Performance Code for Direct Numerical
    Simulations of Turbulent Taylor–Couette Flow.” <i>SoftwareX</i>. Elsevier, 2020.
    <a href="https://doi.org/10.1016/j.softx.2019.100395">https://doi.org/10.1016/j.softx.2019.100395</a>.
  ieee: J. M. Lopez Alonso, D. Feldmann, M. Rampp, A. Vela-Martín, L. Shi, and M.
    Avila, “nsCouette – A high-performance code for direct numerical simulations of
    turbulent Taylor–Couette flow,” <i>SoftwareX</i>, vol. 11. Elsevier, 2020.
  ista: Lopez Alonso JM, Feldmann D, Rampp M, Vela-Martín A, Shi L, Avila M. 2020.
    nsCouette – A high-performance code for direct numerical simulations of turbulent
    Taylor–Couette flow. SoftwareX. 11, 100395.
  mla: Lopez Alonso, Jose M., et al. “NsCouette – A High-Performance Code for Direct
    Numerical Simulations of Turbulent Taylor–Couette Flow.” <i>SoftwareX</i>, vol.
    11, 100395, Elsevier, 2020, doi:<a href="https://doi.org/10.1016/j.softx.2019.100395">10.1016/j.softx.2019.100395</a>.
  short: J.M. Lopez Alonso, D. Feldmann, M. Rampp, A. Vela-Martín, L. Shi, M. Avila,
    SoftwareX 11 (2020).
date_created: 2020-01-26T23:00:35Z
date_published: 2020-01-17T00:00:00Z
date_updated: 2023-08-17T14:29:59Z
day: '17'
ddc:
- '000'
department:
- _id: BjHo
doi: 10.1016/j.softx.2019.100395
external_id:
  arxiv:
  - '1908.00587'
  isi:
  - '000552271200011'
file:
- access_level: open_access
  checksum: 2af1a1a3cc33557b345145276f221668
  content_type: application/pdf
  creator: dernst
  date_created: 2020-01-27T07:32:46Z
  date_updated: 2020-07-14T12:47:56Z
  file_id: '7365'
  file_name: 2020_SoftwareX_Lopez.pdf
  file_size: 679707
  relation: main_file
file_date_updated: 2020-07-14T12:47:56Z
has_accepted_license: '1'
intvolume: '        11'
isi: 1
language:
- iso: eng
month: '01'
oa: 1
oa_version: Published Version
publication: SoftwareX
publication_identifier:
  eissn:
  - '23527110'
publication_status: published
publisher: Elsevier
quality_controlled: '1'
scopus_import: '1'
status: public
title: nsCouette – A high-performance code for direct numerical simulations of turbulent
  Taylor–Couette flow
tmp:
  image: /images/cc_by_nc_nd.png
  legal_code_url: https://creativecommons.org/licenses/by-nc-nd/4.0/legalcode
  name: Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
    (CC BY-NC-ND 4.0)
  short: CC BY-NC-ND (4.0)
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 11
year: '2020'
...
---
_id: '7534'
abstract:
- lang: eng
  text: 'In the past two decades, our understanding of the transition to turbulence
    in shear flows with linearly stable laminar solutions has greatly improved. Regarding
    the susceptibility of the laminar flow, two concepts have been particularly useful:
    the edge states and the minimal seeds. In this nonlinear picture of the transition,
    the basin boundary of turbulence is set by the edge state''s stable manifold and
    this manifold comes closest in energy to the laminar equilibrium at the minimal
    seed. We begin this paper by presenting numerical experiments in which three-dimensional
    perturbations are too energetic to trigger turbulence in pipe flow but they do
    lead to turbulence when their amplitude is reduced. We show that this seemingly
    counterintuitive observation is in fact consistent with the fully nonlinear description
    of the transition mediated by the edge state. In order to understand the physical
    mechanisms behind this process, we measure the turbulent kinetic energy production
    and dissipation rates as a function of the radial coordinate. Our main observation
    is that the transition to turbulence relies on the energy amplification away from
    the wall, as opposed to the turbulence itself, whose energy is predominantly produced
    near the wall. This observation is further supported by the similar analyses on
    the minimal seeds and the edge states. Furthermore, we show that the time evolution
    of production-over-dissipation curves provides a clear distinction between the
    different initial amplification stages of the transition to turbulence from the
    minimal seed.'
article_number: '023903'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Nazmi B
  full_name: Budanur, Nazmi B
  id: 3EA1010E-F248-11E8-B48F-1D18A9856A87
  last_name: Budanur
  orcid: 0000-0003-0423-5010
- first_name: Elena
  full_name: Marensi, Elena
  last_name: Marensi
- first_name: Ashley P.
  full_name: Willis, Ashley P.
  last_name: Willis
- first_name: Björn
  full_name: Hof, Björn
  id: 3A374330-F248-11E8-B48F-1D18A9856A87
  last_name: Hof
  orcid: 0000-0003-2057-2754
citation:
  ama: Budanur NB, Marensi E, Willis AP, Hof B. Upper edge of chaos and the energetics
    of transition in pipe flow. <i>Physical Review Fluids</i>. 2020;5(2). doi:<a href="https://doi.org/10.1103/physrevfluids.5.023903">10.1103/physrevfluids.5.023903</a>
  apa: Budanur, N. B., Marensi, E., Willis, A. P., &#38; Hof, B. (2020). Upper edge
    of chaos and the energetics of transition in pipe flow. <i>Physical Review Fluids</i>.
    American Physical Society. <a href="https://doi.org/10.1103/physrevfluids.5.023903">https://doi.org/10.1103/physrevfluids.5.023903</a>
  chicago: Budanur, Nazmi B, Elena Marensi, Ashley P. Willis, and Björn Hof. “Upper
    Edge of Chaos and the Energetics of Transition in Pipe Flow.” <i>Physical Review
    Fluids</i>. American Physical Society, 2020. <a href="https://doi.org/10.1103/physrevfluids.5.023903">https://doi.org/10.1103/physrevfluids.5.023903</a>.
  ieee: N. B. Budanur, E. Marensi, A. P. Willis, and B. Hof, “Upper edge of chaos
    and the energetics of transition in pipe flow,” <i>Physical Review Fluids</i>,
    vol. 5, no. 2. American Physical Society, 2020.
  ista: Budanur NB, Marensi E, Willis AP, Hof B. 2020. Upper edge of chaos and the
    energetics of transition in pipe flow. Physical Review Fluids. 5(2), 023903.
  mla: Budanur, Nazmi B., et al. “Upper Edge of Chaos and the Energetics of Transition
    in Pipe Flow.” <i>Physical Review Fluids</i>, vol. 5, no. 2, 023903, American
    Physical Society, 2020, doi:<a href="https://doi.org/10.1103/physrevfluids.5.023903">10.1103/physrevfluids.5.023903</a>.
  short: N.B. Budanur, E. Marensi, A.P. Willis, B. Hof, Physical Review Fluids 5 (2020).
date_created: 2020-02-27T10:26:57Z
date_published: 2020-02-21T00:00:00Z
date_updated: 2023-08-18T06:44:46Z
day: '21'
department:
- _id: BjHo
doi: 10.1103/physrevfluids.5.023903
external_id:
  arxiv:
  - '1912.09270'
  isi:
  - '000515065100001'
intvolume: '         5'
isi: 1
issue: '2'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/1912.09270
month: '02'
oa: 1
oa_version: Preprint
publication: Physical Review Fluids
publication_identifier:
  issn:
  - 2469-990X
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
scopus_import: '1'
status: public
title: Upper edge of chaos and the energetics of transition in pipe flow
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 5
year: '2020'
...
---
_id: '7563'
abstract:
- lang: eng
  text: "We introduce “state space persistence analysis” for deducing the symbolic
    dynamics of time series data obtained from high-dimensional chaotic attractors.
    To this end, we adapt a topological data analysis technique known as persistent
    homology for the characterization of state space projections of chaotic trajectories
    and periodic orbits. By comparing the shapes along a chaotic trajectory to those
    of the periodic orbits, state space persistence analysis quantifies the shape
    similarity of chaotic trajectory segments and periodic orbits. We demonstrate
    the method by applying it to the three-dimensional Rössler system and a 30-dimensional
    discretization of the Kuramoto–Sivashinsky partial differential equation in (1+1)
    dimensions.\r\nOne way of studying chaotic attractors systematically is through
    their symbolic dynamics, in which one partitions the state space into qualitatively
    different regions and assigns a symbol to each such region.1–3 This yields a “coarse-grained”
    state space of the system, which can then be reduced to a Markov chain encoding
    all possible transitions between the states of the system. While it is possible
    to obtain the symbolic dynamics of low-dimensional chaotic systems with standard
    tools such as Poincaré maps, when applied to high-dimensional systems such as
    turbulent flows, these tools alone are not sufficient to determine symbolic dynamics.4,5
    In this paper, we develop “state space persistence analysis” and demonstrate that
    it can be utilized to infer the symbolic dynamics in very high-dimensional settings."
article_number: '033109'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Gökhan
  full_name: Yalniz, Gökhan
  id: 66E74FA2-D8BF-11E9-8249-8DE2E5697425
  last_name: Yalniz
  orcid: 0000-0002-8490-9312
- first_name: Nazmi B
  full_name: Budanur, Nazmi B
  id: 3EA1010E-F248-11E8-B48F-1D18A9856A87
  last_name: Budanur
  orcid: 0000-0003-0423-5010
citation:
  ama: Yalniz G, Budanur NB. Inferring symbolic dynamics of chaotic flows from persistence.
    <i>Chaos</i>. 2020;30(3). doi:<a href="https://doi.org/10.1063/1.5122969">10.1063/1.5122969</a>
  apa: Yalniz, G., &#38; Budanur, N. B. (2020). Inferring symbolic dynamics of chaotic
    flows from persistence. <i>Chaos</i>. AIP Publishing. <a href="https://doi.org/10.1063/1.5122969">https://doi.org/10.1063/1.5122969</a>
  chicago: Yalniz, Gökhan, and Nazmi B Budanur. “Inferring Symbolic Dynamics of Chaotic
    Flows from Persistence.” <i>Chaos</i>. AIP Publishing, 2020. <a href="https://doi.org/10.1063/1.5122969">https://doi.org/10.1063/1.5122969</a>.
  ieee: G. Yalniz and N. B. Budanur, “Inferring symbolic dynamics of chaotic flows
    from persistence,” <i>Chaos</i>, vol. 30, no. 3. AIP Publishing, 2020.
  ista: Yalniz G, Budanur NB. 2020. Inferring symbolic dynamics of chaotic flows from
    persistence. Chaos. 30(3), 033109.
  mla: Yalniz, Gökhan, and Nazmi B. Budanur. “Inferring Symbolic Dynamics of Chaotic
    Flows from Persistence.” <i>Chaos</i>, vol. 30, no. 3, 033109, AIP Publishing,
    2020, doi:<a href="https://doi.org/10.1063/1.5122969">10.1063/1.5122969</a>.
  short: G. Yalniz, N.B. Budanur, Chaos 30 (2020).
date_created: 2020-03-04T08:06:25Z
date_published: 2020-03-03T00:00:00Z
date_updated: 2023-08-18T06:47:16Z
day: '03'
department:
- _id: BjHo
doi: 10.1063/1.5122969
external_id:
  arxiv:
  - '1910.04584'
  isi:
  - '000519254800002'
intvolume: '        30'
isi: 1
issue: '3'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://doi.org/10.1063/1.5122969
month: '03'
oa: 1
oa_version: Published Version
publication: Chaos
publication_identifier:
  eissn:
  - 1089-7682
  issn:
  - 1054-1500
publication_status: published
publisher: AIP Publishing
quality_controlled: '1'
scopus_import: '1'
status: public
title: Inferring symbolic dynamics of chaotic flows from persistence
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 30
year: '2020'
...
