---
_id: '519'
abstract:
- lang: eng
text: 'This study treats with the influence of a symmetry-breaking transversal magnetic
field on the nonlinear dynamics of ferrofluidic Taylor-Couette flow – flow confined
between two concentric independently rotating cylinders. We detected alternating
‘flip’ solutions which are flow states featuring typical characteristics of slow-fast-dynamics
in dynamical systems. The flip corresponds to a temporal change in the axial wavenumber
and we find them to appear either as pure 2-fold axisymmetric (due to the symmetry-breaking
nature of the applied transversal magnetic field) or involving non-axisymmetric,
helical modes in its interim solution. The latter ones show features of typical
ribbon solutions. In any case the flip solutions have a preferential first axial
wavenumber which corresponds to the more stable state (slow dynamics) and second
axial wavenumber, corresponding to the short appearing more unstable state (fast
dynamics). However, in both cases the flip time grows exponential with increasing
the magnetic field strength before the flip solutions, living on 2-tori invariant
manifolds, cease to exist, with lifetime going to infinity. Further we show that
ferrofluidic flow turbulence differ from the classical, ordinary (usually at high
Reynolds number) turbulence. The applied magnetic field hinders the free motion
of ferrofluid partials and therefore smoothen typical turbulent quantities and
features so that speaking of mildly chaotic dynamics seems to be a more appropriate
expression for the observed motion. '
acknowledgement: S.Altmeyer is a Serra Húnter Fellow
article_processing_charge: No
article_type: original
author:
- first_name: Sebastian
full_name: Altmeyer, Sebastian
id: 2EE67FDC-F248-11E8-B48F-1D18A9856A87
last_name: Altmeyer
orcid: 0000-0001-5964-0203
citation:
ama: Altmeyer S. Non-linear dynamics and alternating ‘flip’ solutions in ferrofluidic
Taylor-Couette flow. Journal of Magnetism and Magnetic Materials. 2018;452:427-441.
doi:10.1016/j.jmmm.2017.12.073
apa: Altmeyer, S. (2018). Non-linear dynamics and alternating ‘flip’ solutions in
ferrofluidic Taylor-Couette flow. Journal of Magnetism and Magnetic Materials.
Elsevier. https://doi.org/10.1016/j.jmmm.2017.12.073
chicago: Altmeyer, Sebastian. “Non-Linear Dynamics and Alternating ‘Flip’ Solutions
in Ferrofluidic Taylor-Couette Flow.” Journal of Magnetism and Magnetic Materials.
Elsevier, 2018. https://doi.org/10.1016/j.jmmm.2017.12.073.
ieee: S. Altmeyer, “Non-linear dynamics and alternating ‘flip’ solutions in ferrofluidic
Taylor-Couette flow,” Journal of Magnetism and Magnetic Materials, vol.
452. Elsevier, pp. 427–441, 2018.
ista: Altmeyer S. 2018. Non-linear dynamics and alternating ‘flip’ solutions in
ferrofluidic Taylor-Couette flow. Journal of Magnetism and Magnetic Materials.
452, 427–441.
mla: Altmeyer, Sebastian. “Non-Linear Dynamics and Alternating ‘Flip’ Solutions
in Ferrofluidic Taylor-Couette Flow.” Journal of Magnetism and Magnetic Materials,
vol. 452, Elsevier, 2018, pp. 427–41, doi:10.1016/j.jmmm.2017.12.073.
short: S. Altmeyer, Journal of Magnetism and Magnetic Materials 452 (2018) 427–441.
date_created: 2018-12-11T11:46:56Z
date_published: 2018-04-15T00:00:00Z
date_updated: 2023-09-13T09:03:44Z
day: '15'
ddc:
- '530'
department:
- _id: BjHo
doi: 10.1016/j.jmmm.2017.12.073
external_id:
isi:
- '000425547700061'
file:
- access_level: open_access
checksum: 431f5cd4a628d7ca21161f82b14ccb4f
content_type: application/pdf
creator: dernst
date_created: 2020-05-14T14:41:17Z
date_updated: 2020-07-14T12:46:37Z
file_id: '7838'
file_name: 2018_Magnetism_Altmeyer.pdf
file_size: 17309535
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file_date_updated: 2020-07-14T12:46:37Z
has_accepted_license: '1'
intvolume: ' 452'
isi: 1
language:
- iso: eng
month: '04'
oa: 1
oa_version: Submitted Version
page: 427 - 441
publication: Journal of Magnetism and Magnetic Materials
publication_status: published
publisher: Elsevier
publist_id: '7297'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Non-linear dynamics and alternating ‘flip’ solutions in ferrofluidic Taylor-Couette
flow
type: journal_article
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 452
year: '2018'
...
---
_id: '1160'
abstract:
- lang: eng
text: 'We investigate fundamental nonlinear dynamics of ferrofluidic Taylor-Couette
flow - flow confined be-tween two concentric independently rotating cylinders
- consider small aspect ratio by solving the ferro-hydrodynamical equations, carrying
out systematic bifurcation analysis. Without magnetic field, we find steady flow
patterns, previously observed with a simple fluid, such as those containing normal
one- or two vortex cells, as well as anomalous one-cell and twin-cell flow states.
However, when a symmetry-breaking transverse magnetic field is present, all flow
states exhibit stimulated, finite two-fold mode. Various bifurcations between
steady and unsteady states can occur, corresponding to the transitions between
the two-cell and one-cell states. While unsteady, axially oscillating flow states
can arise, we also detect the emergence of new unsteady flow states. In particular,
we uncover two new states: one contains only the azimuthally oscillating solution
in the configuration of the twin-cell flow state, and an-other a rotating flow
state. Topologically, these flow states are a limit cycle and a quasiperiodic
solution on a two-torus, respectively. Emergence of new flow states in addition
to observed ones with classical fluid, indicates that richer but potentially more
controllable dynamics in ferrofluidic flows, as such flow states depend on the
external magnetic field.'
article_number: '40012'
article_processing_charge: No
author:
- first_name: Sebastian
full_name: Altmeyer, Sebastian
id: 2EE67FDC-F248-11E8-B48F-1D18A9856A87
last_name: Altmeyer
orcid: 0000-0001-5964-0203
- first_name: Younghae
full_name: Do, Younghae
last_name: Do
- first_name: Ying
full_name: Lai, Ying
last_name: Lai
citation:
ama: Altmeyer S, Do Y, Lai Y. Dynamics of ferrofluidic flow in the Taylor-Couette
system with a small aspect ratio. Scientific Reports. 2017;7. doi:10.1038/srep40012
apa: Altmeyer, S., Do, Y., & Lai, Y. (2017). Dynamics of ferrofluidic flow in
the Taylor-Couette system with a small aspect ratio. Scientific Reports.
Nature Publishing Group. https://doi.org/10.1038/srep40012
chicago: Altmeyer, Sebastian, Younghae Do, and Ying Lai. “Dynamics of Ferrofluidic
Flow in the Taylor-Couette System with a Small Aspect Ratio.” Scientific Reports.
Nature Publishing Group, 2017. https://doi.org/10.1038/srep40012.
ieee: S. Altmeyer, Y. Do, and Y. Lai, “Dynamics of ferrofluidic flow in the Taylor-Couette
system with a small aspect ratio,” Scientific Reports, vol. 7. Nature Publishing
Group, 2017.
ista: Altmeyer S, Do Y, Lai Y. 2017. Dynamics of ferrofluidic flow in the Taylor-Couette
system with a small aspect ratio. Scientific Reports. 7, 40012.
mla: Altmeyer, Sebastian, et al. “Dynamics of Ferrofluidic Flow in the Taylor-Couette
System with a Small Aspect Ratio.” Scientific Reports, vol. 7, 40012, Nature
Publishing Group, 2017, doi:10.1038/srep40012.
short: S. Altmeyer, Y. Do, Y. Lai, Scientific Reports 7 (2017).
date_created: 2018-12-11T11:50:28Z
date_published: 2017-01-06T00:00:00Z
date_updated: 2023-09-20T11:28:49Z
day: '06'
ddc:
- '532'
department:
- _id: BjHo
doi: 10.1038/srep40012
external_id:
isi:
- '000391269700001'
file:
- access_level: open_access
checksum: 694aa70399444570825099c1a7ec91f2
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:10:16Z
date_updated: 2020-07-14T12:44:36Z
file_id: '4802'
file_name: IST-2017-743-v1+1_srep40012.pdf
file_size: 4546835
relation: main_file
file_date_updated: 2020-07-14T12:44:36Z
has_accepted_license: '1'
intvolume: ' 7'
isi: 1
language:
- iso: eng
license: https://creativecommons.org/licenses/by/4.0/
month: '01'
oa: 1
oa_version: Published Version
publication: Scientific Reports
publication_identifier:
issn:
- '20452322'
publication_status: published
publisher: Nature Publishing Group
publist_id: '6198'
pubrep_id: '743'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Dynamics of ferrofluidic flow in the Taylor-Couette system with a small aspect
ratio
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: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 7
year: '2017'
...
---
_id: '673'
abstract:
- lang: eng
text: We present a numerical study of wavy supercritical cylindrical Couette flow
between counter-rotating cylinders in which the wavy pattern propagates either
prograde with the inner cylinder or retrograde opposite the rotation of the inner
cylinder. The wave propagation reversals from prograde to retrograde and vice
versa occur at distinct values of the inner cylinder Reynolds number when the
associated frequency of the wavy instability vanishes. The reversal occurs for
both twofold and threefold symmetric wavy vortices. Moreover, the wave propagation
reversal only occurs for sufficiently strong counter-rotation. The flow pattern
reversal appears to be intrinsic in the system as either periodic boundary conditions
or fixed end wall boundary conditions for different system sizes always result
in the wave propagation reversal. We present a detailed bifurcation sequence and
parameter space diagram with respect to retrograde behavior of wavy flows. The
retrograde propagation of the instability occurs when the inner Reynolds number
is about two times the outer Reynolds number. The mechanism for the retrograde
propagation is associated with the inviscidly unstable region near the inner cylinder
and the direction of the global average azimuthal velocity. Flow dynamics, spatio-temporal
behavior, global mean angular velocity, and torque of the flow with the wavy pattern
are explored.
article_number: '053103'
article_processing_charge: No
author:
- first_name: Sebastian
full_name: Altmeyer, Sebastian
id: 2EE67FDC-F248-11E8-B48F-1D18A9856A87
last_name: Altmeyer
orcid: 0000-0001-5964-0203
- first_name: Richard
full_name: Lueptow, Richard
last_name: Lueptow
citation:
ama: Altmeyer S, Lueptow R. Wave propagation reversal for wavy vortices in wide
gap counter rotating cylindrical Couette flow. Physical Review E. 2017;95(5).
doi:10.1103/PhysRevE.95.053103
apa: Altmeyer, S., & Lueptow, R. (2017). Wave propagation reversal for wavy
vortices in wide gap counter rotating cylindrical Couette flow. Physical Review
E. American Physical Society. https://doi.org/10.1103/PhysRevE.95.053103
chicago: Altmeyer, Sebastian, and Richard Lueptow. “Wave Propagation Reversal for
Wavy Vortices in Wide Gap Counter Rotating Cylindrical Couette Flow.” Physical
Review E. American Physical Society, 2017. https://doi.org/10.1103/PhysRevE.95.053103.
ieee: S. Altmeyer and R. Lueptow, “Wave propagation reversal for wavy vortices in
wide gap counter rotating cylindrical Couette flow,” Physical Review E,
vol. 95, no. 5. American Physical Society, 2017.
ista: Altmeyer S, Lueptow R. 2017. Wave propagation reversal for wavy vortices in
wide gap counter rotating cylindrical Couette flow. Physical Review E. 95(5),
053103.
mla: Altmeyer, Sebastian, and Richard Lueptow. “Wave Propagation Reversal for Wavy
Vortices in Wide Gap Counter Rotating Cylindrical Couette Flow.” Physical Review
E, vol. 95, no. 5, 053103, American Physical Society, 2017, doi:10.1103/PhysRevE.95.053103.
short: S. Altmeyer, R. Lueptow, Physical Review E 95 (2017).
date_created: 2018-12-11T11:47:50Z
date_published: 2017-05-10T00:00:00Z
date_updated: 2023-10-10T13:30:03Z
day: '10'
department:
- _id: BjHo
doi: 10.1103/PhysRevE.95.053103
intvolume: ' 95'
issue: '5'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/pdf/physics/0505164.pdf
month: '05'
oa: 1
oa_version: Submitted Version
publication: Physical Review E
publication_identifier:
issn:
- 2470-0045
publication_status: published
publisher: American Physical Society
publist_id: '7049'
scopus_import: '1'
status: public
title: Wave propagation reversal for wavy vortices in wide gap counter rotating cylindrical
Couette flow
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 95
year: '2017'
...
---
_id: '463'
abstract:
- lang: eng
text: We investigate transient behaviors induced by magnetic fields on the dynamics
of the flow of a ferrofluid in the gap between two concentric, independently rotating
cylinders. Without applying any magnetic fields, we uncover emergence of flow
states constituted by a combination of a localized spiral state (SPIl) in the
top and bottom of the annulus and different multi-cell flow states (SPI2v, SPI3v)
with toroidally closed vortices in the interior of the bulk (SPIl+2v = SPIl +
SPI2v and SPIl+3v = SPIl + SPI3v). However, when a magnetic field is presented,
we observe the transient behaviors between multi-cell states passing through two
critical thresholds in a strength of an axial (transverse) magnetic field. Before
the first critical threshold of a magnetic field strength, multi-stable states
with different number of cells could be observed. After the first critical threshold,
we find the transient behavior between the three- and two-cell flow states. For
more strength of magnetic field or after the second critical threshold, we discover
that multi-cell states are disappeared and a localized spiral state remains to
be stimulated. The studied transient behavior could be understood by the investigation
of various quantities including a modal kinetic energy, a mode amplitude of the
radial velocity, wavenumber, angular momentum, and torque. In addition, the emergence
of new flow states and the transient behavior between their states in ferrofluidic
flows indicate that richer and potentially controllable dynamics through magnetic
fields could be possible in ferrofluic flow.
article_number: '113112'
article_processing_charge: No
article_type: original
author:
- first_name: Sebastian
full_name: Altmeyer, Sebastian
id: 2EE67FDC-F248-11E8-B48F-1D18A9856A87
last_name: Altmeyer
orcid: 0000-0001-5964-0203
- first_name: Younghae
full_name: Do, Younghae
last_name: Do
- first_name: Soorok
full_name: Ryu, Soorok
last_name: Ryu
citation:
ama: Altmeyer S, Do Y, Ryu S. Transient behavior between multi-cell flow states
in ferrofluidic Taylor-Couette flow. Chaos. 2017;27(11). doi:10.1063/1.5002771
apa: Altmeyer, S., Do, Y., & Ryu, S. (2017). Transient behavior between multi-cell
flow states in ferrofluidic Taylor-Couette flow. Chaos. AIP Publishing.
https://doi.org/10.1063/1.5002771
chicago: Altmeyer, Sebastian, Younghae Do, and Soorok Ryu. “Transient Behavior between
Multi-Cell Flow States in Ferrofluidic Taylor-Couette Flow.” Chaos. AIP
Publishing, 2017. https://doi.org/10.1063/1.5002771.
ieee: S. Altmeyer, Y. Do, and S. Ryu, “Transient behavior between multi-cell flow
states in ferrofluidic Taylor-Couette flow,” Chaos, vol. 27, no. 11. AIP
Publishing, 2017.
ista: Altmeyer S, Do Y, Ryu S. 2017. Transient behavior between multi-cell flow
states in ferrofluidic Taylor-Couette flow. Chaos. 27(11), 113112.
mla: Altmeyer, Sebastian, et al. “Transient Behavior between Multi-Cell Flow States
in Ferrofluidic Taylor-Couette Flow.” Chaos, vol. 27, no. 11, 113112, AIP
Publishing, 2017, doi:10.1063/1.5002771.
short: S. Altmeyer, Y. Do, S. Ryu, Chaos 27 (2017).
date_created: 2018-12-11T11:46:37Z
date_published: 2017-11-01T00:00:00Z
date_updated: 2024-02-28T13:02:12Z
day: '01'
ddc:
- '530'
department:
- _id: BjHo
doi: 10.1063/1.5002771
file:
- access_level: open_access
checksum: 0731f9d416760c1062db258ca51f8bdc
content_type: application/pdf
creator: dernst
date_created: 2019-10-24T15:14:30Z
date_updated: 2020-07-14T12:46:32Z
file_id: '6970'
file_name: 2017_Chaos_Altmeyer.pdf
file_size: 7714020
relation: main_file
file_date_updated: 2020-07-14T12:46:32Z
has_accepted_license: '1'
intvolume: ' 27'
issue: '11'
language:
- iso: eng
month: '11'
oa: 1
oa_version: Published Version
publication: Chaos
publication_identifier:
issn:
- '10541500'
publication_status: published
publisher: AIP Publishing
publist_id: '7358'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Transient behavior between multi-cell flow states in ferrofluidic Taylor-Couette
flow
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 27
year: '2017'
...
---
_id: '1804'
abstract:
- lang: eng
text: It is known that in classical fluids turbulence typically occurs at high Reynolds
numbers. But can turbulence occur at low Reynolds numbers? Here we investigate
the transition to turbulence in the classic Taylor-Couette system in which the
rotating fluids are manufactured ferrofluids with magnetized nanoparticles embedded
in liquid carriers. We find that, in the presence of a magnetic field transverse
to the symmetry axis of the system, turbulence can occur at Reynolds numbers that
are at least one order of magnitude smaller than those in conventional fluids.
This is established by extensive computational ferrohydrodynamics through a detailed
investigation of transitions in the flow structure, and characterization of behaviors
of physical quantities such as the energy, the wave number, and the angular momentum
through the bifurcations. A finding is that, as the magnetic field is increased,
onset of turbulence can be determined accurately and reliably. Our results imply
that experimental investigation of turbulence may be feasible by using ferrofluids.
Our study of transition to and evolution of turbulence in the Taylor-Couette ferrofluidic
flow system provides insights into the challenging problem of turbulence control.
article_number: '10781'
author:
- first_name: Sebastian
full_name: Altmeyer, Sebastian
id: 2EE67FDC-F248-11E8-B48F-1D18A9856A87
last_name: Altmeyer
orcid: 0000-0001-5964-0203
- first_name: Younghae
full_name: Do, Younghae
last_name: Do
- first_name: Ying
full_name: Lai, Ying
last_name: Lai
citation:
ama: Altmeyer S, Do Y, Lai Y. Transition to turbulence in Taylor-Couette ferrofluidic
flow. Scientific Reports. 2015;5. doi:10.1038/srep10781
apa: Altmeyer, S., Do, Y., & Lai, Y. (2015). Transition to turbulence in Taylor-Couette
ferrofluidic flow. Scientific Reports. Nature Publishing Group. https://doi.org/10.1038/srep10781
chicago: Altmeyer, Sebastian, Younghae Do, and Ying Lai. “Transition to Turbulence
in Taylor-Couette Ferrofluidic Flow.” Scientific Reports. Nature Publishing
Group, 2015. https://doi.org/10.1038/srep10781.
ieee: S. Altmeyer, Y. Do, and Y. Lai, “Transition to turbulence in Taylor-Couette
ferrofluidic flow,” Scientific Reports, vol. 5. Nature Publishing Group,
2015.
ista: Altmeyer S, Do Y, Lai Y. 2015. Transition to turbulence in Taylor-Couette
ferrofluidic flow. Scientific Reports. 5, 10781.
mla: Altmeyer, Sebastian, et al. “Transition to Turbulence in Taylor-Couette Ferrofluidic
Flow.” Scientific Reports, vol. 5, 10781, Nature Publishing Group, 2015,
doi:10.1038/srep10781.
short: S. Altmeyer, Y. Do, Y. Lai, Scientific Reports 5 (2015).
date_created: 2018-12-11T11:54:06Z
date_published: 2015-06-12T00:00:00Z
date_updated: 2021-01-12T06:53:18Z
day: '12'
ddc:
- '530'
department:
- _id: BjHo
doi: 10.1038/srep10781
file:
- access_level: open_access
checksum: 7716f582f8c9d82d8f2bf80bf896b440
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:17:26Z
date_updated: 2020-07-14T12:45:16Z
file_id: '5280'
file_name: IST-2016-450-v1+1_srep10781.pdf
file_size: 2449723
relation: main_file
file_date_updated: 2020-07-14T12:45:16Z
has_accepted_license: '1'
intvolume: ' 5'
language:
- iso: eng
month: '06'
oa: 1
oa_version: Published Version
publication: Scientific Reports
publication_status: published
publisher: Nature Publishing Group
publist_id: '5306'
pubrep_id: '450'
quality_controlled: '1'
scopus_import: 1
status: public
title: Transition to turbulence in Taylor-Couette ferrofluidic 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: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 5
year: '2015'
...
---
_id: '1868'
abstract:
- lang: eng
text: We investigate high-dimensional nonlinear dynamical systems exhibiting multiple
resonances under adiabatic parameter variations. Our motivations come from experimental
considerations where time-dependent sweeping of parameters is a practical approach
to probing and characterizing the bifurcations of the system. The question is
whether bifurcations so detected are faithful representations of the bifurcations
intrinsic to the original stationary system. Utilizing a harmonically forced,
closed fluid flow system that possesses multiple resonances and solving the Navier-Stokes
equation under proper boundary conditions, we uncover the phenomenon of the early
effect. Specifically, as a control parameter, e.g., the driving frequency, is
adiabatically increased from an initial value, resonances emerge at frequency
values that are lower than those in the corresponding stationary system. The phenomenon
is established by numerical characterization of physical quantities through the
resonances, which include the kinetic energy and the vorticity field, and a heuristic
analysis based on the concept of instantaneous frequency. A simple formula is
obtained which relates the resonance points in the time-dependent and time-independent
systems. Our findings suggest that, in general, any true bifurcation of a nonlinear
dynamical system can be unequivocally uncovered through adiabatic parameter sweeping,
in spite of a shift in the bifurcation point, which is of value to experimental
studies of nonlinear dynamical systems.
article_number: '022906'
author:
- first_name: Youngyong
full_name: Park, Youngyong
last_name: Park
- first_name: Younghae
full_name: Do, Younghae
last_name: Do
- first_name: Sebastian
full_name: Altmeyer, Sebastian
id: 2EE67FDC-F248-11E8-B48F-1D18A9856A87
last_name: Altmeyer
orcid: 0000-0001-5964-0203
- first_name: Yingcheng
full_name: Lai, Yingcheng
last_name: Lai
- first_name: Gyuwon
full_name: Lee, Gyuwon
last_name: Lee
citation:
ama: Park Y, Do Y, Altmeyer S, Lai Y, Lee G. Early effect in time-dependent, high-dimensional
nonlinear dynamical systems with multiple resonances. Physical Review E.
2015;91(2). doi:10.1103/PhysRevE.91.022906
apa: Park, Y., Do, Y., Altmeyer, S., Lai, Y., & Lee, G. (2015). Early effect
in time-dependent, high-dimensional nonlinear dynamical systems with multiple
resonances. Physical Review E. American Physical Society. https://doi.org/10.1103/PhysRevE.91.022906
chicago: Park, Youngyong, Younghae Do, Sebastian Altmeyer, Yingcheng Lai, and Gyuwon
Lee. “Early Effect in Time-Dependent, High-Dimensional Nonlinear Dynamical Systems
with Multiple Resonances.” Physical Review E. American Physical Society,
2015. https://doi.org/10.1103/PhysRevE.91.022906.
ieee: Y. Park, Y. Do, S. Altmeyer, Y. Lai, and G. Lee, “Early effect in time-dependent,
high-dimensional nonlinear dynamical systems with multiple resonances,” Physical
Review E, vol. 91, no. 2. American Physical Society, 2015.
ista: Park Y, Do Y, Altmeyer S, Lai Y, Lee G. 2015. Early effect in time-dependent,
high-dimensional nonlinear dynamical systems with multiple resonances. Physical
Review E. 91(2), 022906.
mla: Park, Youngyong, et al. “Early Effect in Time-Dependent, High-Dimensional Nonlinear
Dynamical Systems with Multiple Resonances.” Physical Review E, vol. 91,
no. 2, 022906, American Physical Society, 2015, doi:10.1103/PhysRevE.91.022906.
short: Y. Park, Y. Do, S. Altmeyer, Y. Lai, G. Lee, Physical Review E 91 (2015).
date_created: 2018-12-11T11:54:27Z
date_published: 2015-02-09T00:00:00Z
date_updated: 2021-01-12T06:53:44Z
day: '09'
department:
- _id: BjHo
doi: 10.1103/PhysRevE.91.022906
intvolume: ' 91'
issue: '2'
language:
- iso: eng
month: '02'
oa_version: None
publication: Physical Review E
publication_identifier:
issn:
- 1539-3755
publication_status: published
publisher: American Physical Society
publist_id: '5229'
quality_controlled: '1'
scopus_import: 1
status: public
title: Early effect in time-dependent, high-dimensional nonlinear dynamical systems
with multiple resonances
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 91
year: '2015'
...
---
_id: '1588'
abstract:
- lang: eng
text: 'We investigate the Taylor-Couette system where the radius ratio is close
to unity. Systematically increasing the Reynolds number, we observe a number of
previously known transitions, such as one from the classical Taylor vortex flow
(TVF) to wavy vortex flow (WVF) and the transition to fully developed turbulence.
Prior to the onset of turbulence, we observe intermittent bursting patterns of
localized turbulent patches, confirming the experimentally observed pattern of
very short wavelength bursts (VSWBs). A striking finding is that, for a Reynolds
number larger than that for the onset of VSWBs, a new type of intermittently bursting
behavior emerges: patterns of azimuthally closed rings of various orders. We call
them ring-bursting patterns, which surround the cylinder completely but remain
localized and separated in the axial direction through nonturbulent wavy structures.
We employ a number of quantitative measures including the cross-flow energy to
characterize the ring-bursting patterns and to distinguish them from the background
flow. These patterns are interesting because they do not occur in the wide-gap
Taylor-Couette flow systems. The narrow-gap regime is less studied but certainly
deserves further attention to gain deeper insights into complex flow dynamics
in fluids.'
article_number: '053018'
author:
- first_name: Sebastian
full_name: Altmeyer, Sebastian
id: 2EE67FDC-F248-11E8-B48F-1D18A9856A87
last_name: Altmeyer
orcid: 0000-0001-5964-0203
- first_name: Younghae
full_name: Do, Younghae
last_name: Do
- first_name: Ying
full_name: Lai, Ying
last_name: Lai
citation:
ama: Altmeyer S, Do Y, Lai Y. Ring-bursting behavior en route to turbulence in narrow-gap
Taylor-Couette flows. Physical Review E. 2015;92(5). doi:10.1103/PhysRevE.92.053018
apa: Altmeyer, S., Do, Y., & Lai, Y. (2015). Ring-bursting behavior en route
to turbulence in narrow-gap Taylor-Couette flows. Physical Review E. American
Physical Society. https://doi.org/10.1103/PhysRevE.92.053018
chicago: Altmeyer, Sebastian, Younghae Do, and Ying Lai. “Ring-Bursting Behavior
En Route to Turbulence in Narrow-Gap Taylor-Couette Flows.” Physical Review
E. American Physical Society, 2015. https://doi.org/10.1103/PhysRevE.92.053018.
ieee: S. Altmeyer, Y. Do, and Y. Lai, “Ring-bursting behavior en route to turbulence
in narrow-gap Taylor-Couette flows,” Physical Review E, vol. 92, no. 5.
American Physical Society, 2015.
ista: Altmeyer S, Do Y, Lai Y. 2015. Ring-bursting behavior en route to turbulence
in narrow-gap Taylor-Couette flows. Physical Review E. 92(5), 053018.
mla: Altmeyer, Sebastian, et al. “Ring-Bursting Behavior En Route to Turbulence
in Narrow-Gap Taylor-Couette Flows.” Physical Review E, vol. 92, no. 5,
053018, American Physical Society, 2015, doi:10.1103/PhysRevE.92.053018.
short: S. Altmeyer, Y. Do, Y. Lai, Physical Review E 92 (2015).
date_created: 2018-12-11T11:52:53Z
date_published: 2015-11-24T00:00:00Z
date_updated: 2021-01-12T06:51:47Z
day: '24'
department:
- _id: BjHo
doi: 10.1103/PhysRevE.92.053018
intvolume: ' 92'
issue: '5'
language:
- iso: eng
month: '11'
oa_version: None
publication: Physical Review E
publication_status: published
publisher: American Physical Society
publist_id: '5583'
quality_controlled: '1'
scopus_import: 1
status: public
title: Ring-bursting behavior en route to turbulence in narrow-gap Taylor-Couette
flows
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 92
year: '2015'
...
---
_id: '1589'
abstract:
- lang: eng
text: We investigate the dynamics of ferrofluidic wavy vortex flows in the counter-rotating
Taylor-Couette system, with a focus on wavy flows with a mixture of the dominant
azimuthal modes. Without external magnetic field flows are stable and pro-grade
with respect to the rotation of the inner cylinder. More complex behaviors can
arise when an axial or a transverse magnetic field is applied. Depending on the
direction and strength of the field, multi-stable wavy states and bifurcations
can occur. We uncover the phenomenon of flow pattern reversal as the strength
of the magnetic field is increased through a critical value. In between the regimes
of pro-grade and retrograde flow rotations, standing waves with zero angular velocities
can emerge. A striking finding is that, under a transverse magnetic field, a second
reversal in the flow pattern direction can occur, where the flow pattern evolves
into pro-grade rotation again from a retrograde state. Flow reversal is relevant
to intriguing phenomena in nature such as geomagnetic reversal. Our results suggest
that, in ferrofluids, flow pattern reversal can be induced by varying a magnetic
field in a controlled manner, which can be realized in laboratory experiments
with potential applications in the development of modern fluid devices.
article_number: '18589'
article_type: original
author:
- first_name: Sebastian
full_name: Altmeyer, Sebastian
id: 2EE67FDC-F248-11E8-B48F-1D18A9856A87
last_name: Altmeyer
orcid: 0000-0001-5964-0203
- first_name: Younghae
full_name: Do, Younghae
last_name: Do
- first_name: Ying
full_name: Lai, Ying
last_name: Lai
citation:
ama: Altmeyer S, Do Y, Lai Y. Magnetic field induced flow pattern reversal in a
ferrofluidic Taylor-Couette system. Scientific Reports. 2015;5. doi:10.1038/srep18589
apa: Altmeyer, S., Do, Y., & Lai, Y. (2015). Magnetic field induced flow pattern
reversal in a ferrofluidic Taylor-Couette system. Scientific Reports. Nature
Publishing Group. https://doi.org/10.1038/srep18589
chicago: Altmeyer, Sebastian, Younghae Do, and Ying Lai. “Magnetic Field Induced
Flow Pattern Reversal in a Ferrofluidic Taylor-Couette System.” Scientific
Reports. Nature Publishing Group, 2015. https://doi.org/10.1038/srep18589.
ieee: S. Altmeyer, Y. Do, and Y. Lai, “Magnetic field induced flow pattern reversal
in a ferrofluidic Taylor-Couette system,” Scientific Reports, vol. 5. Nature
Publishing Group, 2015.
ista: Altmeyer S, Do Y, Lai Y. 2015. Magnetic field induced flow pattern reversal
in a ferrofluidic Taylor-Couette system. Scientific Reports. 5, 18589.
mla: Altmeyer, Sebastian, et al. “Magnetic Field Induced Flow Pattern Reversal in
a Ferrofluidic Taylor-Couette System.” Scientific Reports, vol. 5, 18589,
Nature Publishing Group, 2015, doi:10.1038/srep18589.
short: S. Altmeyer, Y. Do, Y. Lai, Scientific Reports 5 (2015).
date_created: 2018-12-11T11:52:53Z
date_published: 2015-12-21T00:00:00Z
date_updated: 2021-01-12T06:51:48Z
day: '21'
ddc:
- '530'
- '540'
department:
- _id: BjHo
doi: 10.1038/srep18589
file:
- access_level: open_access
checksum: 927e151674347661ce36eae2818dafdc
content_type: application/pdf
creator: system
date_created: 2018-12-12T10:13:49Z
date_updated: 2020-07-14T12:45:03Z
file_id: '5036'
file_name: IST-2016-472-v1+1_srep18589.pdf
file_size: 2771236
relation: main_file
file_date_updated: 2020-07-14T12:45:03Z
has_accepted_license: '1'
intvolume: ' 5'
language:
- iso: eng
month: '12'
oa: 1
oa_version: Published Version
publication: Scientific Reports
publication_status: published
publisher: Nature Publishing Group
publist_id: '5582'
pubrep_id: '472'
quality_controlled: '1'
scopus_import: 1
status: public
title: Magnetic field induced flow pattern reversal in a ferrofluidic Taylor-Couette
system
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: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 5
year: '2015'
...
---
_id: '2224'
abstract:
- lang: eng
text: This work investigates the transition between different traveling helical
waves (spirals, SPIs) in the setup of differentially independent rotating cylinders.
We use direct numerical simulations to consider an infinite long and periodic
Taylor-Couette apparatus with fixed axial periodicity length. We find so-called
mixed-cross-spirals (MCSs), that can be seen as nonlinear superpositions of SPIs,
to establish stable footbridges connecting SPI states. While bridging the bifurcation
branches of SPIs, the corresponding contributions within the MCS vary continuously
with the control parameters. Here discussed MCSs presenting footbridge solutions
start and end in different SPI branches. Therefore they differ significantly from
the already known MCSs that present bypass solutions (Altmeyer and Hoffmann 2010
New J. Phys. 12 113035). The latter start and end in the same SPI branch, while
they always bifurcate out of those SPI branches with the larger mode amplitude.
Meanwhile, these only appear within the coexisting region of both SPIs. In contrast,
the footbridge solutions can also bifurcate out of the minor SPI contribution.
We also find they exist in regions where only one of the SPIs contributions exists.
In addition, MCS as footbridge solution can appear either stable or unstable.
The latter detected transient solutions offer similar spatio-temporal characteristics
to the flow establishing stable footbridges. Such transition processes are interesting
for pattern-forming systems in general because they accomplish transitions between
traveling waves of different azimuthal wave numbers and have not been described
in the literature yet.
article_number: '025503'
author:
- first_name: Sebastian
full_name: Altmeyer, Sebastian
id: 2EE67FDC-F248-11E8-B48F-1D18A9856A87
last_name: Altmeyer
orcid: 0000-0001-5964-0203
citation:
ama: Altmeyer S. On secondary instabilities generating footbridges between spiral
vortex flow. Fluid Dynamics Research. 2014;46(2). doi:10.1088/0169-5983/46/2/025503
apa: Altmeyer, S. (2014). On secondary instabilities generating footbridges between
spiral vortex flow. Fluid Dynamics Research. IOP Publishing Ltd. https://doi.org/10.1088/0169-5983/46/2/025503
chicago: Altmeyer, Sebastian. “On Secondary Instabilities Generating Footbridges
between Spiral Vortex Flow.” Fluid Dynamics Research. IOP Publishing Ltd.,
2014. https://doi.org/10.1088/0169-5983/46/2/025503.
ieee: S. Altmeyer, “On secondary instabilities generating footbridges between spiral
vortex flow,” Fluid Dynamics Research, vol. 46, no. 2. IOP Publishing Ltd.,
2014.
ista: Altmeyer S. 2014. On secondary instabilities generating footbridges between
spiral vortex flow. Fluid Dynamics Research. 46(2), 025503.
mla: Altmeyer, Sebastian. “On Secondary Instabilities Generating Footbridges between
Spiral Vortex Flow.” Fluid Dynamics Research, vol. 46, no. 2, 025503, IOP
Publishing Ltd., 2014, doi:10.1088/0169-5983/46/2/025503.
short: S. Altmeyer, Fluid Dynamics Research 46 (2014).
date_created: 2018-12-11T11:56:25Z
date_published: 2014-04-01T00:00:00Z
date_updated: 2021-01-12T06:56:07Z
day: '01'
department:
- _id: BjHo
doi: 10.1088/0169-5983/46/2/025503
intvolume: ' 46'
issue: '2'
language:
- iso: eng
month: '04'
oa_version: None
publication: Fluid Dynamics Research
publication_identifier:
issn:
- '01695983'
publication_status: published
publisher: IOP Publishing Ltd.
publist_id: '4740'
quality_controlled: '1'
scopus_import: 1
status: public
title: On secondary instabilities generating footbridges between spiral vortex flow
type: journal_article
user_id: 4435EBFC-F248-11E8-B48F-1D18A9856A87
volume: 46
year: '2014'
...