---
_id: '10654'
abstract:
- lang: eng
text: "Directed percolation (DP) has recently emerged as a possible solution to
the century old puzzle surrounding the transition to turbulence. Multiple model
studies reported DP exponents, however, experimental evidence is limited since
the largest possible observation times are orders of magnitude shorter than the
flows’ characteristic timescales. An exception is cylindrical Couette flow where
the limit is not temporal, but rather the realizable system size. We present experiments
in a Couette setup of unprecedented azimuthal and axial aspect ratios. Approaching
the critical point to within less than 0.1% we determine five critical exponents,
all of which are in excellent agreement with the 2+1D DP universality class. The
complex dynamics encountered at \r\nthe onset of turbulence can hence be fully
rationalized within the framework of statistical mechanics."
acknowledged_ssus:
- _id: M-Shop
acknowledgement: "We thank T.Menner, T.Asenov, P. Maier and the Miba machine shop
of IST Austria for their valuable support in all technical aspects. We thank Marc
Avila for comments on the manuscript. This work was supported by a grant from the
Simons Foundation (662960, B.H.). We acknowledge the European Research Council under
the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement
306589 for financial support. K.A.\r\nacknowledges funding from the Central Research
Development Fund of the University of Bremen, grant number ZF04B /2019/FB04 Avila
Kerstin (”Independent Project for Postdocs”). L.K. was supported by the European
Union’s Horizon 2020 Research and innovation programme under the Marie Sklodowska-Curie
grant agreement No. 754411.\r\n"
article_number: '014502'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Lukasz
full_name: Klotz, Lukasz
id: 2C9AF1C2-F248-11E8-B48F-1D18A9856A87
last_name: Klotz
orcid: 0000-0003-1740-7635
- first_name: Grégoire M
full_name: Lemoult, Grégoire M
id: 4787FE80-F248-11E8-B48F-1D18A9856A87
last_name: Lemoult
- first_name: Kerstin
full_name: Avila, Kerstin
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: Klotz L, Lemoult GM, Avila K, Hof B. Phase transition to turbulence in spatially
extended shear flows. Physical Review Letters. 2022;128(1). doi:10.1103/PhysRevLett.128.014502
apa: Klotz, L., Lemoult, G. M., Avila, K., & Hof, B. (2022). Phase transition
to turbulence in spatially extended shear flows. Physical Review Letters.
American Physical Society. https://doi.org/10.1103/PhysRevLett.128.014502
chicago: Klotz, Lukasz, Grégoire M Lemoult, Kerstin Avila, and Björn Hof. “Phase
Transition to Turbulence in Spatially Extended Shear Flows.” Physical Review
Letters. American Physical Society, 2022. https://doi.org/10.1103/PhysRevLett.128.014502.
ieee: L. Klotz, G. M. Lemoult, K. Avila, and B. Hof, “Phase transition to turbulence
in spatially extended shear flows,” Physical Review Letters, vol. 128,
no. 1. American Physical Society, 2022.
ista: Klotz L, Lemoult GM, Avila K, Hof B. 2022. Phase transition to turbulence
in spatially extended shear flows. Physical Review Letters. 128(1), 014502.
mla: Klotz, Lukasz, et al. “Phase Transition to Turbulence in Spatially Extended
Shear Flows.” Physical Review Letters, vol. 128, no. 1, 014502, American
Physical Society, 2022, doi:10.1103/PhysRevLett.128.014502.
short: L. Klotz, G.M. Lemoult, K. Avila, B. Hof, Physical Review Letters 128 (2022).
date_created: 2022-01-23T23:01:28Z
date_published: 2022-01-05T00:00:00Z
date_updated: 2023-08-02T13:59:19Z
day: '05'
department:
- _id: BjHo
doi: 10.1103/PhysRevLett.128.014502
ec_funded: 1
external_id:
arxiv:
- '2111.14894'
isi:
- '000748271700010'
pmid:
- '35061458'
intvolume: ' 128'
isi: 1
issue: '1'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/2111.14894
month: '01'
oa: 1
oa_version: Preprint
pmid: 1
project:
- _id: 260C2330-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '754411'
name: ISTplus - Postdoctoral Fellowships
- _id: 25152F3A-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '306589'
name: Decoding the complexity of turbulence at its origin
- _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'
scopus_import: '1'
status: public
title: Phase transition to turbulence in spatially extended shear flows
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 128
year: '2022'
...
---
_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. Journal of Fluid Mechanics.
2021;912. doi:10.1017/jfm.2020.1089'
apa: 'Klotz, L., Pavlenko, A. M., & Wesfreid, J. E. (2021). Experimental measurements
in plane Couette-Poiseuille flow: Dynamics of the large- and small-scale flow.
Journal of Fluid Mechanics. Cambridge University Press. https://doi.org/10.1017/jfm.2020.1089'
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.”
Journal of Fluid Mechanics. Cambridge University Press, 2021. https://doi.org/10.1017/jfm.2020.1089.'
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,”
Journal of Fluid Mechanics, 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.” Journal of Fluid Mechanics,
vol. 912, A24, Cambridge University Press, 2021, doi:10.1017/jfm.2020.1089.'
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. Journal of Fluid Mechanics.
2021;915. doi:10.1017/jfm.2021.89
apa: Liu, T., Semin, B., Klotz, L., Godoy-Diana, R., Wesfreid, J. E., & Mullin,
T. (2021). Decay of streaks and rolls in plane Couette-Poiseuille flow. Journal
of Fluid Mechanics. Cambridge University Press. https://doi.org/10.1017/jfm.2021.89
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.” Journal
of Fluid Mechanics. Cambridge University Press, 2021. https://doi.org/10.1017/jfm.2021.89.
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,” Journal of Fluid
Mechanics, 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.”
Journal of Fluid Mechanics, vol. 915, A65, Cambridge University Press,
2021, doi:10.1017/jfm.2021.89.
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: '5943'
abstract:
- lang: eng
text: The hairpin instability of a jet in a crossflow (JICF) for a low jet-to-crossflow
velocity ratio is investigated experimentally for a velocity ratio range of R
∈ (0.14, 0.75) and crossflow Reynolds numbers ReD ∈ (260, 640). From spectral
analysis we characterize the Strouhal number and amplitude of the hairpin instability
as a function of R and ReD. We demonstrate that the dynamics of the hairpins is
well described by the Landau model, and, hence, that the instability occurs through
Hopf bifurcation, similarly to other hydrodynamical oscillators such as wake behind
different bluff bodies. Using the Landau model, we determine the precise threshold
values of hairpin shedding. We also study the spatial dependence of this hydrodynamical
instability, which shows a global behaviour.
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Lukasz
full_name: Klotz, Lukasz
id: 2C9AF1C2-F248-11E8-B48F-1D18A9856A87
last_name: Klotz
orcid: 0000-0003-1740-7635
- first_name: Konrad
full_name: Gumowski, Konrad
last_name: Gumowski
- first_name: José Eduardo
full_name: Wesfreid, José Eduardo
last_name: Wesfreid
citation:
ama: Klotz L, Gumowski K, Wesfreid JE. Experiments on a jet in a crossflow in the
low-velocity-ratio regime. Journal of Fluid Mechanics. 2019;863:386-406.
doi:10.1017/jfm.2018.974
apa: Klotz, L., Gumowski, K., & Wesfreid, J. E. (2019). Experiments on a jet
in a crossflow in the low-velocity-ratio regime. Journal of Fluid Mechanics.
Cambridge University Press. https://doi.org/10.1017/jfm.2018.974
chicago: Klotz, Lukasz, Konrad Gumowski, and José Eduardo Wesfreid. “Experiments
on a Jet in a Crossflow in the Low-Velocity-Ratio Regime.” Journal of Fluid
Mechanics. Cambridge University Press, 2019. https://doi.org/10.1017/jfm.2018.974.
ieee: L. Klotz, K. Gumowski, and J. E. Wesfreid, “Experiments on a jet in a crossflow
in the low-velocity-ratio regime,” Journal of Fluid Mechanics, vol. 863.
Cambridge University Press, pp. 386–406, 2019.
ista: Klotz L, Gumowski K, Wesfreid JE. 2019. Experiments on a jet in a crossflow
in the low-velocity-ratio regime. Journal of Fluid Mechanics. 863, 386–406.
mla: Klotz, Lukasz, et al. “Experiments on a Jet in a Crossflow in the Low-Velocity-Ratio
Regime.” Journal of Fluid Mechanics, vol. 863, Cambridge University Press,
2019, pp. 386–406, doi:10.1017/jfm.2018.974.
short: L. Klotz, K. Gumowski, J.E. Wesfreid, Journal of Fluid Mechanics 863 (2019)
386–406.
date_created: 2019-02-10T22:59:15Z
date_published: 2019-03-25T00:00:00Z
date_updated: 2023-08-24T14:43:13Z
day: '25'
department:
- _id: BjHo
doi: 10.1017/jfm.2018.974
ec_funded: 1
external_id:
arxiv:
- '1902.07931'
isi:
- '000526029100016'
intvolume: ' 863'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1902.07931
month: '03'
oa: 1
oa_version: Preprint
page: 386-406
project:
- _id: 260C2330-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '754411'
name: ISTplus - Postdoctoral Fellowships
publication: Journal of Fluid Mechanics
publication_status: published
publisher: Cambridge University Press
quality_controlled: '1'
scopus_import: '1'
status: public
title: Experiments on a jet in a crossflow in the low-velocity-ratio regime
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 863
year: '2019'
...
---
_id: '513'
abstract:
- lang: eng
text: 'We present an experimental setup that creates a shear flow with zero mean
advection velocity achieved by counterbalancing the nonzero streamwise pressure
gradient by moving boundaries, which generates plane Couette-Poiseuille flow.
We obtain experimental results in the transitional regime for this flow. Using
flow visualization, we characterize the subcritical transition to turbulence in
Couette-Poiseuille flow and show the existence of turbulent spots generated by
a permanent perturbation. Due to the zero mean advection velocity of the base
profile, these turbulent structures are nearly stationary. We distinguish two
regions of the turbulent spot: the active turbulent core, which is characterized
by waviness of the streaks similar to traveling waves, and the surrounding region,
which includes in addition the weak undisturbed streaks and oblique waves at the
laminar-turbulent interface. We also study the dependence of the size of these
two regions on Reynolds number. Finally, we show that the traveling waves move
in the downstream (Poiseuille) direction.'
article_number: '043904'
author:
- first_name: Lukasz
full_name: Klotz, Lukasz
id: 2C9AF1C2-F248-11E8-B48F-1D18A9856A87
last_name: Klotz
orcid: 0000-0003-1740-7635
- first_name: Grégoire M
full_name: Lemoult, Grégoire M
id: 4787FE80-F248-11E8-B48F-1D18A9856A87
last_name: Lemoult
- first_name: Idalia
full_name: Frontczak, Idalia
last_name: Frontczak
- first_name: Laurette
full_name: Tuckerman, Laurette
last_name: Tuckerman
- first_name: José
full_name: Wesfreid, José
last_name: Wesfreid
citation:
ama: 'Klotz L, Lemoult GM, Frontczak I, Tuckerman L, Wesfreid J. Couette-Poiseuille
flow experiment with zero mean advection velocity: Subcritical transition to turbulence.
Physical Review Fluids. 2017;2(4). doi:10.1103/PhysRevFluids.2.043904'
apa: 'Klotz, L., Lemoult, G. M., Frontczak, I., Tuckerman, L., & Wesfreid, J.
(2017). Couette-Poiseuille flow experiment with zero mean advection velocity:
Subcritical transition to turbulence. Physical Review Fluids. American
Physical Society. https://doi.org/10.1103/PhysRevFluids.2.043904'
chicago: 'Klotz, Lukasz, Grégoire M Lemoult, Idalia Frontczak, Laurette Tuckerman,
and José Wesfreid. “Couette-Poiseuille Flow Experiment with Zero Mean Advection
Velocity: Subcritical Transition to Turbulence.” Physical Review Fluids.
American Physical Society, 2017. https://doi.org/10.1103/PhysRevFluids.2.043904.'
ieee: 'L. Klotz, G. M. Lemoult, I. Frontczak, L. Tuckerman, and J. Wesfreid, “Couette-Poiseuille
flow experiment with zero mean advection velocity: Subcritical transition to turbulence,”
Physical Review Fluids, vol. 2, no. 4. American Physical Society, 2017.'
ista: 'Klotz L, Lemoult GM, Frontczak I, Tuckerman L, Wesfreid J. 2017. Couette-Poiseuille
flow experiment with zero mean advection velocity: Subcritical transition to turbulence.
Physical Review Fluids. 2(4), 043904.'
mla: 'Klotz, Lukasz, et al. “Couette-Poiseuille Flow Experiment with Zero Mean Advection
Velocity: Subcritical Transition to Turbulence.” Physical Review Fluids,
vol. 2, no. 4, 043904, American Physical Society, 2017, doi:10.1103/PhysRevFluids.2.043904.'
short: L. Klotz, G.M. Lemoult, I. Frontczak, L. Tuckerman, J. Wesfreid, Physical
Review Fluids 2 (2017).
date_created: 2018-12-11T11:46:54Z
date_published: 2017-04-01T00:00:00Z
date_updated: 2021-01-12T08:01:16Z
day: '01'
department:
- _id: BjHo
doi: 10.1103/PhysRevFluids.2.043904
intvolume: ' 2'
issue: '4'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1704.02619
month: '04'
oa: 1
oa_version: Preprint
publication: Physical Review Fluids
publication_status: published
publisher: American Physical Society
publist_id: '7306'
quality_controlled: '1'
scopus_import: 1
status: public
title: 'Couette-Poiseuille flow experiment with zero mean advection velocity: Subcritical
transition to turbulence'
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 2
year: '2017'
...