---
_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. Proceedings of the National Academy of Sciences of the United
States of America. 2020;117(21):11233-11239. doi:10.1073/pnas.1913716117
apa: 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. National
Academy of Sciences. https://doi.org/10.1073/pnas.1913716117
chicago: Xu, Duo, Atul Varshney, Xingyu Ma, Baofang Song, Michael Riedl, Marc Avila,
and Björn Hof. “Nonlinear Hydrodynamic Instability and Turbulence in Pulsatile
Flow.” Proceedings of the National Academy of Sciences of the United States
of America. National Academy of Sciences, 2020. https://doi.org/10.1073/pnas.1913716117.
ieee: D. Xu et al., “Nonlinear hydrodynamic instability and turbulence in
pulsatile flow,” Proceedings of the National Academy of Sciences of the United
States of America, 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.” Proceedings of the National Academy of Sciences of the United States
of America, vol. 117, no. 21, National Academy of Sciences, 2020, pp. 11233–39,
doi:10.1073/pnas.1913716117.
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: 2026-04-07T13:29:13Z
day: '26'
department:
- _id: BjHo
doi: 10.1073/pnas.1913716117
ec_funded: 1
external_id:
arxiv:
- '2005.11190'
isi:
- '000536797100014'
pmid:
- '32393637'
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
pmid: 1
project:
- _id: 238B8092-32DE-11EA-91FC-C7463DDC885E
call_identifier: FWF
grant_number: I04188
name: Instabilities in pulsating pipe flow in 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:
- 1091-6490
issn:
- 0027-8424
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: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 117
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:10.15479/AT:ISTA:8350
apa: Shamipour, S. (2020). Bulk actin dynamics drive phase segregation in zebrafish
oocytes . Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:8350
chicago: Shamipour, Shayan. “Bulk Actin Dynamics Drive Phase Segregation in Zebrafish
Oocytes .” Institute of Science and Technology Austria, 2020. https://doi.org/10.15479/AT:ISTA:8350.
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. Bulk Actin Dynamics Drive Phase Segregation in Zebrafish
Oocytes . Institute of Science and Technology Austria, 2020, doi:10.15479/AT:ISTA:8350.
short: S. Shamipour, Bulk Actin Dynamics Drive Phase Segregation in Zebrafish Oocytes
, Institute of Science and Technology Austria, 2020.
corr_author: '1'
date_created: 2020-09-09T11:12:10Z
date_published: 2020-09-09T00:00:00Z
date_updated: 2025-09-11T07:08:52Z
day: '09'
ddc:
- '570'
degree_awarded: PhD
department:
- _id: BjHo
- _id: CaHe
doi: 10.15479/AT:ISTA:8350
file:
- access_level: closed
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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checksum: 1b44c57f04d7e8a6fe41b1c9c55a52a3
content_type: application/pdf
creator: sshamip
date_created: 2020-09-09T11:06:13Z
date_updated: 2021-09-11T22:30:05Z
embargo: 2021-09-10
file_id: '8352'
file_name: Shayan-Thesis-Final.pdf
file_size: 23729605
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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: '7001'
relation: part_of_dissertation
status: public
- id: '6508'
relation: part_of_dissertation
status: public
- id: '735'
relation: part_of_dissertation
status: public
- id: '661'
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: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2020'
...
---
OA_place: publisher
_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:10.15479/AT:ISTA:7258
apa: Scarselli, D. (2020). New approaches to reduce friction in turbulent pipe
flow. Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:7258
chicago: Scarselli, Davide. “New Approaches to Reduce Friction in Turbulent Pipe
Flow.” Institute of Science and Technology Austria, 2020. https://doi.org/10.15479/AT:ISTA:7258.
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. New Approaches to Reduce Friction in Turbulent Pipe Flow.
Institute of Science and Technology Austria, 2020, doi:10.15479/AT:ISTA:7258.
short: D. Scarselli, New Approaches to Reduce Friction in Turbulent Pipe Flow, Institute
of Science and Technology Austria, 2020.
corr_author: '1'
date_created: 2020-01-12T16:07:26Z
date_published: 2020-01-13T00:00:00Z
date_updated: 2026-04-08T07:28:22Z
day: '13'
ddc:
- '532'
degree_awarded: PhD
department:
- _id: BjHo
doi: 10.15479/AT:ISTA:7258
ec_funded: 1
file:
- access_level: closed
checksum: 4df1ab24e9896635106adde5a54615bf
content_type: application/zip
creator: dscarsel
date_created: 2020-01-12T15:57:14Z
date_updated: 2021-01-13T23:30:05Z
embargo_to: open_access
file_id: '7259'
file_name: 2020_Scarselli_Thesis.zip
file_size: 26640830
relation: source_file
- access_level: open_access
checksum: 48659ab98e3414293c7a721385c2fd1c
content_type: application/pdf
creator: dscarsel
date_created: 2020-01-12T15:56:14Z
date_updated: 2021-01-13T23:30:05Z
embargo: 2021-01-12
file_id: '7260'
file_name: 2020_Scarselli_Thesis.pdf
file_size: 8515844
relation: main_file
file_date_updated: 2021-01-13T23:30:05Z
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: '422'
relation: part_of_dissertation
status: public
- id: '461'
relation: part_of_dissertation
status: public
- id: '6228'
relation: part_of_dissertation
status: public
- id: '6486'
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: ba8df636-2132-11f1-aed0-ed93e2281fdd
year: '2020'
...
---
_id: '5878'
abstract:
- lang: eng
text: We consider the motion of a droplet bouncing on a vibrating bath of the same
fluid in the presence of a central potential. We formulate a rotation symmetry-reduced
description of this system, which allows for the straightforward application of
dynamical systems theory tools. As an illustration of the utility of the symmetry
reduction, we apply it to a model of the pilot-wave system with a central harmonic
force. We begin our analysis by identifying local bifurcations and the onset of
chaos. We then describe the emergence of chaotic regions and their merging bifurcations,
which lead to the formation of a global attractor. In this final regime, the droplet’s
angular momentum spontaneously changes its sign as observed in the experiments
of Perrard et al.
article_number: '013122'
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: Marc
full_name: Fleury, Marc
last_name: Fleury
citation:
ama: 'Budanur NB, Fleury M. State space geometry of the chaotic pilot-wave hydrodynamics.
Chaos: An Interdisciplinary Journal of Nonlinear Science. 2019;29(1). doi:10.1063/1.5058279'
apa: 'Budanur, N. B., & Fleury, M. (2019). State space geometry of the chaotic
pilot-wave hydrodynamics. Chaos: An Interdisciplinary Journal of Nonlinear
Science. AIP Publishing. https://doi.org/10.1063/1.5058279'
chicago: 'Budanur, Nazmi B, and Marc Fleury. “State Space Geometry of the Chaotic
Pilot-Wave Hydrodynamics.” Chaos: An Interdisciplinary Journal of Nonlinear
Science. AIP Publishing, 2019. https://doi.org/10.1063/1.5058279.'
ieee: 'N. B. Budanur and M. Fleury, “State space geometry of the chaotic pilot-wave
hydrodynamics,” Chaos: An Interdisciplinary Journal of Nonlinear Science,
vol. 29, no. 1. AIP Publishing, 2019.'
ista: 'Budanur NB, Fleury M. 2019. State space geometry of the chaotic pilot-wave
hydrodynamics. Chaos: An Interdisciplinary Journal of Nonlinear Science. 29(1),
013122.'
mla: 'Budanur, Nazmi B., and Marc Fleury. “State Space Geometry of the Chaotic Pilot-Wave
Hydrodynamics.” Chaos: An Interdisciplinary Journal of Nonlinear Science,
vol. 29, no. 1, 013122, AIP Publishing, 2019, doi:10.1063/1.5058279.'
short: 'N.B. Budanur, M. Fleury, Chaos: An Interdisciplinary Journal of Nonlinear
Science 29 (2019).'
date_created: 2019-01-23T08:35:09Z
date_published: 2019-01-22T00:00:00Z
date_updated: 2023-08-25T10:16:11Z
day: '22'
department:
- _id: BjHo
doi: 10.1063/1.5058279
external_id:
arxiv:
- '1812.09011'
isi:
- '000457409100028'
intvolume: ' 29'
isi: 1
issue: '1'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1812.09011
month: '01'
oa: 1
oa_version: Preprint
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'
related_material:
link:
- relation: erratum
url: https://aip.scitation.org/doi/abs/10.1063/1.5097157
scopus_import: '1'
status: public
title: State space geometry of the chaotic pilot-wave hydrodynamics
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 29
year: '2019'
...
---
_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: 2025-04-14T07:43:59Z
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: '6014'
abstract:
- lang: eng
text: Speed of sound waves in gases and liquids are governed by the compressibility
of the medium. There exists another type of non-dispersive wave where the wave
speed depends on stress instead of elasticity of the medium. A well-known example
is the Alfven wave, which propagates through plasma permeated by a magnetic field
with the speed determined by magnetic tension. An elastic analogue of Alfven waves
has been predicted in a flow of dilute polymer solution where the elastic stress
of the stretching polymers determines the elastic wave speed. Here we present
quantitative evidence of elastic Alfven waves in elastic turbulence of a viscoelastic
creeping flow between two obstacles in channel flow. The key finding in the experimental
proof is a nonlinear dependence of the elastic wave speed cel on the Weissenberg
number Wi, which deviates from predictions based on a model of linear polymer
elasticity.
article_number: '652'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Atul
full_name: Varshney, Atul
id: 2A2006B2-F248-11E8-B48F-1D18A9856A87
last_name: Varshney
orcid: 0000-0002-3072-5999
- first_name: Victor
full_name: Steinberg, Victor
last_name: Steinberg
citation:
ama: Varshney A, Steinberg V. Elastic alfven waves in elastic turbulence. Nature
Communications. 2019;10. doi:10.1038/s41467-019-08551-0
apa: Varshney, A., & Steinberg, V. (2019). Elastic alfven waves in elastic turbulence.
Nature Communications. Springer Nature. https://doi.org/10.1038/s41467-019-08551-0
chicago: Varshney, Atul, and Victor Steinberg. “Elastic Alfven Waves in Elastic
Turbulence.” Nature Communications. Springer Nature, 2019. https://doi.org/10.1038/s41467-019-08551-0.
ieee: A. Varshney and V. Steinberg, “Elastic alfven waves in elastic turbulence,”
Nature Communications, vol. 10. Springer Nature, 2019.
ista: Varshney A, Steinberg V. 2019. Elastic alfven waves in elastic turbulence.
Nature Communications. 10, 652.
mla: Varshney, Atul, and Victor Steinberg. “Elastic Alfven Waves in Elastic Turbulence.”
Nature Communications, vol. 10, 652, Springer Nature, 2019, doi:10.1038/s41467-019-08551-0.
short: A. Varshney, V. Steinberg, Nature Communications 10 (2019).
corr_author: '1'
date_created: 2019-02-15T07:10:46Z
date_published: 2019-02-08T00:00:00Z
date_updated: 2025-04-14T07:43:46Z
day: '08'
ddc:
- '530'
department:
- _id: BjHo
doi: 10.1038/s41467-019-08551-0
ec_funded: 1
external_id:
arxiv:
- '1902.03763'
isi:
- '000458175300001'
pmid:
- '30737403'
file:
- access_level: open_access
checksum: d3acf07eaad95ec040d8e8565fc9ac37
content_type: application/pdf
creator: dernst
date_created: 2019-02-15T07:15:00Z
date_updated: 2020-07-14T12:47:17Z
file_id: '6015'
file_name: 2019_NatureComm_Varshney.pdf
file_size: 1331490
relation: main_file
file_date_updated: 2020-07-14T12:47:17Z
has_accepted_license: '1'
intvolume: ' 10'
isi: 1
language:
- iso: eng
month: '02'
oa: 1
oa_version: Published Version
pmid: 1
project:
- _id: 260C2330-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '754411'
name: ISTplus - Postdoctoral Fellowships
publication: Nature Communications
publication_identifier:
issn:
- 2041-1723
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
status: public
title: Elastic alfven waves in elastic turbulence
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: 10
year: '2019'
...
---
_id: '6069'
abstract:
- lang: eng
text: Electron transport in two-dimensional conducting materials such as graphene,
with dominant electron–electron interaction, exhibits unusual vortex flow that
leads to a nonlocal current-field relation (negative resistance), distinct from
the classical Ohm’s law. The transport behavior of these materials is best described
by low Reynolds number hydrodynamics, where the constitutive pressure–speed relation
is Stoke’s law. Here we report evidence of such vortices observed in a viscous
flow of Newtonian fluid in a microfluidic device consisting of a rectangular cavity—analogous
to the electronic system. We extend our experimental observations to elliptic
cavities of different eccentricities, and validate them by numerically solving
bi-harmonic equation obtained for the viscous flow with no-slip boundary conditions.
We verify the existence of a predicted threshold at which vortices appear. Strikingly,
we find that a two-dimensional theoretical model captures the essential features
of three-dimensional Stokes flow in experiments.
article_number: '937'
article_processing_charge: No
author:
- first_name: Jonathan
full_name: Mayzel, Jonathan
last_name: Mayzel
- first_name: Victor
full_name: Steinberg, Victor
last_name: Steinberg
- first_name: Atul
full_name: Varshney, Atul
id: 2A2006B2-F248-11E8-B48F-1D18A9856A87
last_name: Varshney
orcid: 0000-0002-3072-5999
citation:
ama: Mayzel J, Steinberg V, Varshney A. Stokes flow analogous to viscous electron
current in graphene. Nature Communications. 2019;10. doi:10.1038/s41467-019-08916-5
apa: Mayzel, J., Steinberg, V., & Varshney, A. (2019). Stokes flow analogous
to viscous electron current in graphene. Nature Communications. Springer
Nature. https://doi.org/10.1038/s41467-019-08916-5
chicago: Mayzel, Jonathan, Victor Steinberg, and Atul Varshney. “Stokes Flow Analogous
to Viscous Electron Current in Graphene.” Nature Communications. Springer
Nature, 2019. https://doi.org/10.1038/s41467-019-08916-5.
ieee: J. Mayzel, V. Steinberg, and A. Varshney, “Stokes flow analogous to viscous
electron current in graphene,” Nature Communications, vol. 10. Springer
Nature, 2019.
ista: Mayzel J, Steinberg V, Varshney A. 2019. Stokes flow analogous to viscous
electron current in graphene. Nature Communications. 10, 937.
mla: Mayzel, Jonathan, et al. “Stokes Flow Analogous to Viscous Electron Current
in Graphene.” Nature Communications, vol. 10, 937, Springer Nature, 2019,
doi:10.1038/s41467-019-08916-5.
short: J. Mayzel, V. Steinberg, A. Varshney, Nature Communications 10 (2019).
corr_author: '1'
date_created: 2019-03-05T13:18:30Z
date_published: 2019-02-26T00:00:00Z
date_updated: 2025-04-14T07:44:00Z
day: '26'
ddc:
- '530'
- '532'
department:
- _id: BjHo
doi: 10.1038/s41467-019-08916-5
ec_funded: 1
external_id:
isi:
- '000459704600001'
file:
- access_level: open_access
checksum: 61192fc49e0d44907c2a4fe384e4b97f
content_type: application/pdf
creator: dernst
date_created: 2019-03-05T13:33:04Z
date_updated: 2020-07-14T12:47:18Z
file_id: '6070'
file_name: 2019_NatureComm_Mayzel.pdf
file_size: 2646391
relation: main_file
file_date_updated: 2020-07-14T12:47:18Z
has_accepted_license: '1'
intvolume: ' 10'
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: Nature Communications
publication_identifier:
issn:
- 2041-1723
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
status: public
title: Stokes flow analogous to viscous electron current in graphene
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: 10
year: '2019'
...
---
_id: '6779'
abstract:
- lang: eng
text: "Recent studies suggest that unstable recurrent solutions of the Navier-Stokes
equation provide new insights\r\ninto dynamics of turbulent flows. In this study,
we compute an extensive network of dynamical connections\r\nbetween such solutions
in a weakly turbulent quasi-two-dimensional Kolmogorov flow that lies in the inversion
symmetric subspace. In particular, we find numerous isolated heteroclinic connections
between different\r\ntypes of solutions—equilibria, periodic, and quasiperiodic
orbits—as well as continua of connections forming\r\nhigher-dimensional connecting
manifolds. We also compute a homoclinic connection of a periodic orbit and\r\nprovide
strong evidence that the associated homoclinic tangle forms the chaotic repeller
that underpins transient\r\nturbulence in the symmetric subspace."
article_number: '013112'
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: Ravi Kumar
full_name: Pallantla, Ravi Kumar
last_name: Pallantla
- first_name: Michael F.
full_name: Schatz, Michael F.
last_name: Schatz
- first_name: Roman O.
full_name: Grigoriev, Roman O.
last_name: Grigoriev
citation:
ama: Suri B, Pallantla RK, Schatz MF, Grigoriev RO. Heteroclinic and homoclinic
connections in a Kolmogorov-like flow. Physical Review E. 2019;100(1).
doi:10.1103/physreve.100.013112
apa: Suri, B., Pallantla, R. K., Schatz, M. F., & Grigoriev, R. O. (2019). Heteroclinic
and homoclinic connections in a Kolmogorov-like flow. Physical Review E.
American Physical Society. https://doi.org/10.1103/physreve.100.013112
chicago: Suri, Balachandra, Ravi Kumar Pallantla, Michael F. Schatz, and Roman O.
Grigoriev. “Heteroclinic and Homoclinic Connections in a Kolmogorov-like Flow.”
Physical Review E. American Physical Society, 2019. https://doi.org/10.1103/physreve.100.013112.
ieee: B. Suri, R. K. Pallantla, M. F. Schatz, and R. O. Grigoriev, “Heteroclinic
and homoclinic connections in a Kolmogorov-like flow,” Physical Review E,
vol. 100, no. 1. American Physical Society, 2019.
ista: Suri B, Pallantla RK, Schatz MF, Grigoriev RO. 2019. Heteroclinic and homoclinic
connections in a Kolmogorov-like flow. Physical Review E. 100(1), 013112.
mla: Suri, Balachandra, et al. “Heteroclinic and Homoclinic Connections in a Kolmogorov-like
Flow.” Physical Review E, vol. 100, no. 1, 013112, American Physical Society,
2019, doi:10.1103/physreve.100.013112.
short: B. Suri, R.K. Pallantla, M.F. Schatz, R.O. Grigoriev, Physical Review E 100
(2019).
date_created: 2019-08-09T09:40:41Z
date_published: 2019-07-25T00:00:00Z
date_updated: 2025-04-15T06:50:28Z
day: '25'
ddc:
- '532'
department:
- _id: BjHo
doi: 10.1103/physreve.100.013112
ec_funded: 1
external_id:
arxiv:
- '1907.05860'
isi:
- '000477911800012'
intvolume: ' 100'
isi: 1
issue: '1'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1907.05860
month: '07'
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 E
publication_identifier:
eissn:
- 2470-0053
issn:
- 2470-0045
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
scopus_import: '1'
status: public
title: Heteroclinic and homoclinic connections in a Kolmogorov-like flow
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 100
year: '2019'
...
---
_id: '6978'
abstract:
- lang: eng
text: In pipes and channels, the onset of turbulence is initially dominated by localizedtransients, which lead to sustained turbulence through their collective dynamics. In thepresent
work, we study numerically the localized turbulence in pipe flow and elucidate
astate space structure that gives rise to transient chaos. Starting from the basin
boundaryseparating laminar and turbulent flow, we identify transverse homoclinic orbits, thepresence
of which necessitates a homoclinic tangle and chaos. A direct consequence ofthe
homoclinic tangle is the fractal nature of the laminar-turbulent boundary, which
wasconjectured in various earlier studies. By mapping the transverse intersections
between thestable and unstable manifold of a periodic orbit, we identify the gateways
that promote anescape from turbulence.
acknowledged_ssus:
- _id: ScienComp
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: Akshunna
full_name: Dogra, Akshunna
last_name: Dogra
- 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, Dogra A, Hof B. Geometry of transient chaos in streamwise-localized
pipe flow turbulence. Physical Review Fluids. 2019;4(10):102401. doi:10.1103/PhysRevFluids.4.102401
apa: Budanur, N. B., Dogra, A., & Hof, B. (2019). Geometry of transient chaos
in streamwise-localized pipe flow turbulence. Physical Review Fluids. American
Physical Society. https://doi.org/10.1103/PhysRevFluids.4.102401
chicago: Budanur, Nazmi B, Akshunna Dogra, and Björn Hof. “Geometry of Transient
Chaos in Streamwise-Localized Pipe Flow Turbulence.” Physical Review Fluids.
American Physical Society, 2019. https://doi.org/10.1103/PhysRevFluids.4.102401.
ieee: N. B. Budanur, A. Dogra, and B. Hof, “Geometry of transient chaos in streamwise-localized
pipe flow turbulence,” Physical Review Fluids, vol. 4, no. 10. American
Physical Society, p. 102401, 2019.
ista: Budanur NB, Dogra A, Hof B. 2019. Geometry of transient chaos in streamwise-localized
pipe flow turbulence. Physical Review Fluids. 4(10), 102401.
mla: Budanur, Nazmi B., et al. “Geometry of Transient Chaos in Streamwise-Localized
Pipe Flow Turbulence.” Physical Review Fluids, vol. 4, no. 10, American
Physical Society, 2019, p. 102401, doi:10.1103/PhysRevFluids.4.102401.
short: N.B. Budanur, A. Dogra, B. Hof, Physical Review Fluids 4 (2019) 102401.
date_created: 2019-11-04T10:04:01Z
date_published: 2019-10-01T00:00:00Z
date_updated: 2023-08-30T07:20:03Z
day: '01'
department:
- _id: BjHo
doi: 10.1103/PhysRevFluids.4.102401
external_id:
arxiv:
- '1810.02211'
isi:
- '000493510400001'
intvolume: ' 4'
isi: 1
issue: '10'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1810.02211
month: '10'
oa: 1
oa_version: Preprint
page: '102401'
publication: Physical Review Fluids
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
scopus_import: '1'
status: public
title: Geometry of transient chaos in streamwise-localized pipe flow turbulence
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 4
year: '2019'
...
---
_id: '7397'
abstract:
- lang: eng
text: Polymer additives can substantially reduce the drag of turbulent flows and
the upperlimit, the so called “maximum drag reduction” (MDR) asymptote is universal,
i.e. inde-pendent of the type of polymer and solvent used. Until recently, the
consensus was that,in this limit, flows are in a marginal state where only a minimal
level of turbulence activ-ity persists. Observations in direct numerical simulations
using minimal sized channelsappeared to support this view and reported long “hibernation” periods where turbu-lence
is marginalized. In simulations of pipe flow we find that, indeed, with increasingWeissenberg
number (Wi), turbulence expresses long periods of hibernation if the domainsize
is small. However, with increasing pipe length, the temporal hibernation continuouslyalters
to spatio-temporal intermittency and here the flow consists of turbulent puffs
sur-rounded by laminar flow. Moreover, upon an increase in Wi, the flow fully
relaminarises,in agreement with recent experiments. At even larger Wi, a different
instability is en-countered causing a drag increase towards MDR. Our findings
hence link earlier minimalflow unit simulations with recent experiments and confirm
that the addition of polymersinitially suppresses Newtonian turbulence and leads
to a reverse transition. The MDRstate on the other hand results from a separate
instability and the underlying dynamicscorresponds to the recently proposed state
of elasto-inertial-turbulence (EIT).
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: George H
full_name: Choueiri, George H
id: 448BD5BC-F248-11E8-B48F-1D18A9856A87
last_name: Choueiri
- first_name: Björn
full_name: Hof, Björn
id: 3A374330-F248-11E8-B48F-1D18A9856A87
last_name: Hof
orcid: 0000-0003-2057-2754
citation:
ama: Lopez Alonso JM, Choueiri GH, Hof B. Dynamics of viscoelastic pipe flow at
low Reynolds numbers in the maximum drag reduction limit. Journal of Fluid
Mechanics. 2019;874:699-719. doi:10.1017/jfm.2019.486
apa: Lopez Alonso, J. M., Choueiri, G. H., & Hof, B. (2019). Dynamics of viscoelastic
pipe flow at low Reynolds numbers in the maximum drag reduction limit. Journal
of Fluid Mechanics. Cambridge University Press. https://doi.org/10.1017/jfm.2019.486
chicago: Lopez Alonso, Jose M, George H Choueiri, and Björn Hof. “Dynamics of Viscoelastic
Pipe Flow at Low Reynolds Numbers in the Maximum Drag Reduction Limit.” Journal
of Fluid Mechanics. Cambridge University Press, 2019. https://doi.org/10.1017/jfm.2019.486.
ieee: J. M. Lopez Alonso, G. H. Choueiri, and B. Hof, “Dynamics of viscoelastic
pipe flow at low Reynolds numbers in the maximum drag reduction limit,” Journal
of Fluid Mechanics, vol. 874. Cambridge University Press, pp. 699–719, 2019.
ista: Lopez Alonso JM, Choueiri GH, Hof B. 2019. Dynamics of viscoelastic pipe flow
at low Reynolds numbers in the maximum drag reduction limit. Journal of Fluid
Mechanics. 874, 699–719.
mla: Lopez Alonso, Jose M., et al. “Dynamics of Viscoelastic Pipe Flow at Low Reynolds
Numbers in the Maximum Drag Reduction Limit.” Journal of Fluid Mechanics,
vol. 874, Cambridge University Press, 2019, pp. 699–719, doi:10.1017/jfm.2019.486.
short: J.M. Lopez Alonso, G.H. Choueiri, B. Hof, Journal of Fluid Mechanics 874
(2019) 699–719.
date_created: 2020-01-29T16:05:19Z
date_published: 2019-09-10T00:00:00Z
date_updated: 2025-05-14T11:21:59Z
day: '10'
department:
- _id: BjHo
doi: 10.1017/jfm.2019.486
external_id:
arxiv:
- '1808.04080'
isi:
- '000475349900001'
intvolume: ' 874'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1808.04080
month: '09'
oa: 1
oa_version: Preprint
page: 699-719
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: Dynamics of viscoelastic pipe flow at low Reynolds numbers in the maximum drag
reduction limit
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 874
year: '2019'
...
---
_id: '7197'
abstract:
- lang: eng
text: During bacterial cell division, the tubulin-homolog FtsZ forms a ring-like
structure at the center of the cell. This Z-ring not only organizes the division
machinery, but treadmilling of FtsZ filaments was also found to play a key role
in distributing proteins at the division site. What regulates the architecture,
dynamics and stability of the Z-ring is currently unknown, but FtsZ-associated
proteins are known to play an important role. Here, using an in vitro reconstitution
approach, we studied how the well-conserved protein ZapA affects FtsZ treadmilling
and filament organization into large-scale patterns. Using high-resolution fluorescence
microscopy and quantitative image analysis, we found that ZapA cooperatively increases
the spatial order of the filament network, but binds only transiently to FtsZ
filaments and has no effect on filament length and treadmilling velocity. Together,
our data provides a model for how FtsZ-associated proteins can increase the precision
and stability of the bacterial cell division machinery in a switch-like manner.
acknowledged_ssus:
- _id: LifeSc
- _id: Bio
article_number: '5744'
article_processing_charge: No
article_type: original
author:
- first_name: Paulo R
full_name: Dos Santos Caldas, Paulo R
id: 38FCDB4C-F248-11E8-B48F-1D18A9856A87
last_name: Dos Santos Caldas
orcid: 0000-0001-6730-4461
- first_name: Maria D
full_name: Lopez Pelegrin, Maria D
id: 319AA9CE-F248-11E8-B48F-1D18A9856A87
last_name: Lopez Pelegrin
- first_name: Daniel J. G.
full_name: Pearce, Daniel J. G.
last_name: Pearce
- 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: Jan
full_name: Brugués, Jan
last_name: Brugués
- first_name: Martin
full_name: Loose, Martin
id: 462D4284-F248-11E8-B48F-1D18A9856A87
last_name: Loose
orcid: 0000-0001-7309-9724
citation:
ama: Dos Santos Caldas PR, Lopez Pelegrin MD, Pearce DJG, Budanur NB, Brugués J,
Loose M. Cooperative ordering of treadmilling filaments in cytoskeletal networks
of FtsZ and its crosslinker ZapA. Nature Communications. 2019;10. doi:10.1038/s41467-019-13702-4
apa: Dos Santos Caldas, P. R., Lopez Pelegrin, M. D., Pearce, D. J. G., Budanur,
N. B., Brugués, J., & Loose, M. (2019). Cooperative ordering of treadmilling
filaments in cytoskeletal networks of FtsZ and its crosslinker ZapA. Nature
Communications. Springer Nature. https://doi.org/10.1038/s41467-019-13702-4
chicago: Dos Santos Caldas, Paulo R, Maria D Lopez Pelegrin, Daniel J. G. Pearce,
Nazmi B Budanur, Jan Brugués, and Martin Loose. “Cooperative Ordering of Treadmilling
Filaments in Cytoskeletal Networks of FtsZ and Its Crosslinker ZapA.” Nature
Communications. Springer Nature, 2019. https://doi.org/10.1038/s41467-019-13702-4.
ieee: P. R. Dos Santos Caldas, M. D. Lopez Pelegrin, D. J. G. Pearce, N. B. Budanur,
J. Brugués, and M. Loose, “Cooperative ordering of treadmilling filaments in cytoskeletal
networks of FtsZ and its crosslinker ZapA,” Nature Communications, vol.
10. Springer Nature, 2019.
ista: Dos Santos Caldas PR, Lopez Pelegrin MD, Pearce DJG, Budanur NB, Brugués J,
Loose M. 2019. Cooperative ordering of treadmilling filaments in cytoskeletal
networks of FtsZ and its crosslinker ZapA. Nature Communications. 10, 5744.
mla: Dos Santos Caldas, Paulo R., et al. “Cooperative Ordering of Treadmilling Filaments
in Cytoskeletal Networks of FtsZ and Its Crosslinker ZapA.” Nature Communications,
vol. 10, 5744, Springer Nature, 2019, doi:10.1038/s41467-019-13702-4.
short: P.R. Dos Santos Caldas, M.D. Lopez Pelegrin, D.J.G. Pearce, N.B. Budanur,
J. Brugués, M. Loose, Nature Communications 10 (2019).
corr_author: '1'
date_created: 2019-12-20T12:22:57Z
date_published: 2019-12-17T00:00:00Z
date_updated: 2026-04-08T07:26:30Z
day: '17'
ddc:
- '570'
department:
- _id: MaLo
- _id: BjHo
doi: 10.1038/s41467-019-13702-4
ec_funded: 1
external_id:
isi:
- '000503009300001'
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file_id: '7208'
file_name: 2019_NatureComm_Caldas.pdf
file_size: 8488733
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has_accepted_license: '1'
intvolume: ' 10'
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language:
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month: '12'
oa: 1
oa_version: Published Version
project:
- _id: 2595697A-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '679239'
name: Self-Organization of the Bacterial Cell
- _id: 260D98C8-B435-11E9-9278-68D0E5697425
name: Reconstitution of Bacterial Cell Division Using Purified Components
publication: Nature Communications
publication_identifier:
issn:
- 2041-1723
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
related_material:
record:
- id: '8358'
relation: dissertation_contains
status: public
scopus_import: '1'
status: public
title: Cooperative ordering of treadmilling filaments in cytoskeletal networks of
FtsZ and its crosslinker ZapA
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: 10
year: '2019'
...
---
OA_place: publisher
_id: '6957'
abstract:
- lang: eng
text: "In many shear flows like pipe flow, plane Couette flow, plane Poiseuille
flow, etc. turbulence emerges subcritically. Here, when subjected to strong enough
perturbations, the flow becomes turbulent in spite of the laminar base flow being
linearly stable. The nature of this instability has puzzled the scientific community
for decades. At onset, turbulence appears in localized patches and flows are spatio-temporally
intermittent. In pipe flow the localized turbulent structures are referred to
as puffs and in planar flows like plane Couette and channel flow, patches arise
in the form of localized oblique bands. In this thesis, we study the onset of
turbulence in channel flow in direct numerical simulations from a dynamical system
theory perspective, as well as by performing experiments in a large aspect ratio
channel.\r\n\r\nThe aim of the experimental work is to determine the critical
Reynolds number where turbulence first becomes sustained. Recently, the onset
of turbulence has been described in analogy to absorbing state phase transition
(i.e. directed percolation). In particular, it has been shown that the critical
point can be estimated from the competition between spreading and decay processes.
Here, by performing experiments, we identify the mechanisms underlying turbulence
proliferation in channel flow and find the critical Reynolds number, above which
turbulence becomes sustained. Above the critical point, the continuous growth
at the tip of the stripes outweighs the stochastic shedding of turbulent patches
at the tail and the stripes expand. For growing stripes, the probability to decay
decreases while the probability of stripe splitting increases. Consequently, and
unlike for the puffs in pipe flow, neither of these two processes is time-independent
i.e. memoryless. Coupling between stripe expansion and creation of new stripes
via splitting leads to a significantly lower critical point ($Re_c=670+/-10$)
than most earlier studies suggest. \r\n\r\nWhile the above approach sheds light
on how turbulence first becomes sustained, it provides no insight into the origin
of the stripes themselves. In the numerical part of the thesis we investigate
how turbulent stripes form from invariant solutions of the Navier-Stokes equations.
The origin of these turbulent stripes can be identified by applying concepts from
the dynamical system theory. In doing so, we identify the exact coherent structures
underlying stripes and their bifurcations and how they give rise to the turbulent
attractor in phase space. We first report a family of localized nonlinear traveling
wave solutions of the Navier-Stokes equations in channel flow. These solutions
show structural similarities with turbulent stripes in experiments like obliqueness,
quasi-streamwise streaks and vortices, etc. A parametric study of these traveling
wave solution is performed, with parameters like Reynolds number, stripe tilt
angle and domain size, including the stability of the solutions. These solutions
emerge through saddle-node bifurcations and form a phase space skeleton for the
turbulent stripes observed in the experiments. The lower branches of these TW
solutions at different tilt angles undergo Hopf bifurcation and new solutions
branches of relative periodic orbits emerge. These RPO solutions do not belong
to the same family and therefore the routes to chaos for different angles are
different. \r\n\r\nIn shear flows, turbulence at onset is transient in nature.
\ Consequently,turbulence can not be tracked to lower Reynolds numbers, where
the dynamics may simplify. Before this happens, turbulence becomes short-lived
and laminarizes. In the last part of the thesis, we show that using numerical
simulations we can continue turbulent stripes in channel flow past the 'relaminarization
barrier' all the way to their origin. Here, turbulent stripe dynamics simplifies
and the fluctuations are no longer stochastic and the stripe settles down to a
relative periodic orbit. This relative periodic orbit originates from the aforementioned
traveling wave solutions. Starting from the relative periodic orbit, a small increase
in speed i.e. Reynolds number gives rise to chaos and the attractor dimension
sharply increases in contrast to the classical transition scenario where the instabilities
affect the flow globally and give rise to much more gradual route to turbulence."
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Chaitanya S
full_name: Paranjape, Chaitanya S
id: 3D85B7C4-F248-11E8-B48F-1D18A9856A87
last_name: Paranjape
citation:
ama: Paranjape CS. Onset of turbulence in plane Poiseuille flow. 2019. doi:10.15479/AT:ISTA:6957
apa: Paranjape, C. S. (2019). Onset of turbulence in plane Poiseuille flow.
Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:6957
chicago: Paranjape, Chaitanya S. “Onset of Turbulence in Plane Poiseuille Flow.”
Institute of Science and Technology Austria, 2019. https://doi.org/10.15479/AT:ISTA:6957.
ieee: C. S. Paranjape, “Onset of turbulence in plane Poiseuille flow,” Institute
of Science and Technology Austria, 2019.
ista: Paranjape CS. 2019. Onset of turbulence in plane Poiseuille flow. Institute
of Science and Technology Austria.
mla: Paranjape, Chaitanya S. Onset of Turbulence in Plane Poiseuille Flow.
Institute of Science and Technology Austria, 2019, doi:10.15479/AT:ISTA:6957.
short: C.S. Paranjape, Onset of Turbulence in Plane Poiseuille Flow, Institute of
Science and Technology Austria, 2019.
corr_author: '1'
date_created: 2019-10-22T12:08:43Z
date_published: 2019-10-24T00:00:00Z
date_updated: 2026-04-08T07:46:58Z
day: '24'
ddc:
- '532'
degree_awarded: PhD
department:
- _id: BjHo
doi: 10.15479/AT:ISTA:6957
file:
- access_level: closed
checksum: 7ba298ba0ce7e1d11691af6b8eaf0a0a
content_type: application/zip
creator: cparanjape
date_created: 2019-10-23T09:54:43Z
date_updated: 2020-07-14T12:47:46Z
file_id: '6962'
file_name: Chaitanya_Paranjape_source_files_tex_figures.zip
file_size: 45828099
relation: source_file
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checksum: 642697618314e31ac31392da7909c2d9
content_type: application/pdf
creator: cparanjape
date_created: 2019-10-23T10:37:09Z
date_updated: 2020-07-14T12:47:46Z
file_id: '6963'
file_name: Chaitanya_Paranjape_Thesis.pdf
file_size: 19504197
relation: main_file
file_date_updated: 2020-07-14T12:47:46Z
has_accepted_license: '1'
keyword:
- Instabilities
- Turbulence
- Nonlinear dynamics
language:
- iso: eng
month: '10'
oa: 1
oa_version: Published Version
page: '138'
publication_identifier:
eissn:
- 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
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: Onset of turbulence in plane Poiseuille flow
type: dissertation
user_id: ba8df636-2132-11f1-aed0-ed93e2281fdd
year: '2019'
...
---
_id: '6413'
abstract:
- lang: eng
text: Phase-field methods have long been used to model the flow of immiscible fluids.
Their ability to naturally capture interface topological changes is widely recognized,
but their accuracy in simulating flows of real fluids in practical geometries
is not established. We here quantitatively investigate the convergence of the
phase-field method to the sharp-interface limit with simulations of two-phase
pipe flow. We focus on core-annular flows, in which a highly viscous fluid is
lubricated by a less viscous fluid, and validate our simulations with an analytic
laminar solution, a formal linear stability analysis and also in the fully nonlinear
regime. We demonstrate the ability of the phase-field method to accurately deal
with non-rectangular geometry, strong advection, unsteady fluctuations and large
viscosity contrast. We argue that phase-field methods are very promising for quantitatively
studying moderately turbulent flows, especially at high concentrations of the
disperse phase.
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Baofang
full_name: Song, Baofang
last_name: Song
- first_name: Carlos
full_name: Plana, Carlos
last_name: Plana
- 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: Marc
full_name: Avila, Marc
last_name: Avila
citation:
ama: Song B, Plana C, Lopez Alonso JM, Avila M. Phase-field simulation of core-annular
pipe flow. International Journal of Multiphase Flow. 2019;117:14-24. doi:10.1016/j.ijmultiphaseflow.2019.04.027
apa: Song, B., Plana, C., Lopez Alonso, J. M., & Avila, M. (2019). Phase-field
simulation of core-annular pipe flow. International Journal of Multiphase Flow.
Elsevier. https://doi.org/10.1016/j.ijmultiphaseflow.2019.04.027
chicago: Song, Baofang, Carlos Plana, Jose M Lopez Alonso, and Marc Avila. “Phase-Field
Simulation of Core-Annular Pipe Flow.” International Journal of Multiphase
Flow. Elsevier, 2019. https://doi.org/10.1016/j.ijmultiphaseflow.2019.04.027.
ieee: B. Song, C. Plana, J. M. Lopez Alonso, and M. Avila, “Phase-field simulation
of core-annular pipe flow,” International Journal of Multiphase Flow, vol.
117. Elsevier, pp. 14–24, 2019.
ista: Song B, Plana C, Lopez Alonso JM, Avila M. 2019. Phase-field simulation of
core-annular pipe flow. International Journal of Multiphase Flow. 117, 14–24.
mla: Song, Baofang, et al. “Phase-Field Simulation of Core-Annular Pipe Flow.” International
Journal of Multiphase Flow, vol. 117, Elsevier, 2019, pp. 14–24, doi:10.1016/j.ijmultiphaseflow.2019.04.027.
short: B. Song, C. Plana, J.M. Lopez Alonso, M. Avila, International Journal of
Multiphase Flow 117 (2019) 14–24.
date_created: 2019-05-13T07:58:35Z
date_published: 2019-08-01T00:00:00Z
date_updated: 2026-04-16T09:49:27Z
day: '01'
department:
- _id: BjHo
doi: 10.1016/j.ijmultiphaseflow.2019.04.027
external_id:
arxiv:
- '1902.07351'
isi:
- '000474496000002'
intvolume: ' 117'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1902.07351
month: '08'
oa: 1
oa_version: Preprint
page: 14-24
publication: International Journal of Multiphase Flow
publication_identifier:
issn:
- 0301-9322
publication_status: published
publisher: Elsevier
quality_controlled: '1'
scopus_import: '1'
status: public
title: Phase-field simulation of core-annular pipe flow
type: journal_article
user_id: ba8df636-2132-11f1-aed0-ed93e2281fdd
volume: 117
year: '2019'
...
---
_id: '6508'
abstract:
- lang: eng
text: Segregation of maternal determinants within the oocyte constitutes the first
step in embryo patterning. In zebrafish oocytes, extensive ooplasmic streaming
leads to the segregation of ooplasm from yolk granules along the animal-vegetal
axis of the oocyte. Here, we 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 oocyte. This wave functions in segregation by both pulling ooplasm animally
and pushing yolk granules vegetally. Using biophysical experimentation and theory,
we show that ooplasm pulling is mediated by bulk actin network flows exerting
friction forces on the ooplasm, while yolk granule pushing is achieved by a mechanism
closely resembling actin comet formation on yolk granules. Our study defines a
novel role of cell-cycle-controlled bulk actin polymerization waves in oocyte
polarization via ooplasmic segregation.
acknowledged_ssus:
- _id: Bio
- _id: PreCl
acknowledgement: We would like to thank Pierre Recho, Guillaume Salbreux, and Silvia
Grigolon for advice on the theory, Lila Solnica-Krezel for kindly providing us with
zebrafish dachsous mutants, members of the Heisenberg and Hannezo groups for fruitful
discussions, and the Bioimaging and zebrafish facilities at IST Austria for their
continuous support. This project has received funding from the European Union (European
Research Council Advanced Grant 742573 to C.P.H.) and from the Austrian Science
Fund (FWF) (P 31639 to E.H.).
article_processing_charge: No
article_type: original
author:
- first_name: Shayan
full_name: Shamipour, Shayan
id: 40B34FE2-F248-11E8-B48F-1D18A9856A87
last_name: Shamipour
- first_name: Roland
full_name: Kardos, Roland
id: 4039350E-F248-11E8-B48F-1D18A9856A87
last_name: Kardos
- first_name: Shi-lei
full_name: Xue, Shi-lei
id: 31D2C804-F248-11E8-B48F-1D18A9856A87
last_name: Xue
- first_name: Björn
full_name: Hof, Björn
id: 3A374330-F248-11E8-B48F-1D18A9856A87
last_name: Hof
orcid: 0000-0003-2057-2754
- first_name: Edouard B
full_name: Hannezo, Edouard B
id: 3A9DB764-F248-11E8-B48F-1D18A9856A87
last_name: Hannezo
orcid: 0000-0001-6005-1561
- 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
citation:
ama: Shamipour S, Kardos R, Xue S, Hof B, Hannezo EB, Heisenberg C-PJ. Bulk actin
dynamics drive phase segregation in zebrafish oocytes. Cell. 2019;177(6):1463-1479.e18.
doi:10.1016/j.cell.2019.04.030
apa: Shamipour, S., Kardos, R., Xue, S., Hof, B., Hannezo, E. B., & Heisenberg,
C.-P. J. (2019). Bulk actin dynamics drive phase segregation in zebrafish oocytes.
Cell. Elsevier. https://doi.org/10.1016/j.cell.2019.04.030
chicago: Shamipour, Shayan, Roland Kardos, Shi-lei Xue, Björn Hof, Edouard B Hannezo,
and Carl-Philipp J Heisenberg. “Bulk Actin Dynamics Drive Phase Segregation in
Zebrafish Oocytes.” Cell. Elsevier, 2019. https://doi.org/10.1016/j.cell.2019.04.030.
ieee: S. Shamipour, R. Kardos, S. Xue, B. Hof, E. B. Hannezo, and C.-P. J. Heisenberg,
“Bulk actin dynamics drive phase segregation in zebrafish oocytes,” Cell,
vol. 177, no. 6. Elsevier, p. 1463–1479.e18, 2019.
ista: Shamipour S, Kardos R, Xue S, Hof B, Hannezo EB, Heisenberg C-PJ. 2019. Bulk
actin dynamics drive phase segregation in zebrafish oocytes. Cell. 177(6), 1463–1479.e18.
mla: Shamipour, Shayan, et al. “Bulk Actin Dynamics Drive Phase Segregation in Zebrafish
Oocytes.” Cell, vol. 177, no. 6, Elsevier, 2019, p. 1463–1479.e18, doi:10.1016/j.cell.2019.04.030.
short: S. Shamipour, R. Kardos, S. Xue, B. Hof, E.B. Hannezo, C.-P.J. Heisenberg,
Cell 177 (2019) 1463–1479.e18.
date_created: 2019-06-02T21:59:12Z
date_published: 2019-05-30T00:00:00Z
date_updated: 2026-06-07T22:30:09Z
day: '30'
ddc:
- '570'
department:
- _id: CaHe
- _id: EdHa
- _id: BjHo
doi: 10.1016/j.cell.2019.04.030
ec_funded: 1
external_id:
isi:
- '000469415100013'
pmid:
- '31080065'
file:
- access_level: open_access
checksum: aea43726d80e35ce3885073a5f05c3e3
content_type: application/pdf
creator: dernst
date_created: 2020-10-21T07:22:34Z
date_updated: 2020-10-21T07:22:34Z
file_id: '8686'
file_name: 2019_Cell_Shamipour_accepted.pdf
file_size: 3356292
relation: main_file
success: 1
file_date_updated: 2020-10-21T07:22:34Z
has_accepted_license: '1'
intvolume: ' 177'
isi: 1
issue: '6'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://doi.org/10.1016/j.cell.2019.04.030
month: '05'
oa: 1
oa_version: Published Version
page: 1463-1479.e18
pmid: 1
project:
- _id: 260F1432-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '742573'
name: Interaction and feedback between cell mechanics and fate specification in
vertebrate gastrulation
- _id: 268294B6-B435-11E9-9278-68D0E5697425
call_identifier: FWF
grant_number: P31639
name: Active mechano-chemical description of the cell cytoskeleton
publication: Cell
publication_identifier:
eissn:
- 1097-4172
issn:
- 0092-8674
publication_status: published
publisher: Elsevier
quality_controlled: '1'
related_material:
link:
- description: News on IST Homepage
relation: press_release
url: https://ist.ac.at/en/news/how-the-cytoplasm-separates-from-the-yolk/
record:
- id: '8350'
relation: dissertation_contains
status: public
scopus_import: '1'
status: public
title: Bulk actin dynamics drive phase segregation in zebrafish oocytes
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 177
year: '2019'
...
---
_id: '7001'
acknowledged_ssus:
- _id: PreCl
- _id: Bio
article_processing_charge: No
article_type: original
author:
- first_name: Cornelia
full_name: Schwayer, Cornelia
id: 3436488C-F248-11E8-B48F-1D18A9856A87
last_name: Schwayer
orcid: 0000-0001-5130-2226
- first_name: Shayan
full_name: Shamipour, Shayan
id: 40B34FE2-F248-11E8-B48F-1D18A9856A87
last_name: Shamipour
- first_name: Kornelija
full_name: Pranjic-Ferscha, Kornelija
id: 4362B3C2-F248-11E8-B48F-1D18A9856A87
last_name: Pranjic-Ferscha
- first_name: Alexandra
full_name: Schauer, Alexandra
id: 30A536BA-F248-11E8-B48F-1D18A9856A87
last_name: Schauer
orcid: 0000-0001-7659-9142
- first_name: M
full_name: Balda, M
last_name: Balda
- first_name: M
full_name: Tada, M
last_name: Tada
- first_name: K
full_name: Matter, K
last_name: Matter
- 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
citation:
ama: Schwayer C, Shamipour S, Pranjic-Ferscha K, et al. Mechanosensation of tight
junctions depends on ZO-1 phase separation and flow. Cell. 2019;179(4):937-952.e18.
doi:10.1016/j.cell.2019.10.006
apa: Schwayer, C., Shamipour, S., Pranjic-Ferscha, K., Schauer, A., Balda, M., Tada,
M., … Heisenberg, C.-P. J. (2019). Mechanosensation of tight junctions depends
on ZO-1 phase separation and flow. Cell. Cell Press. https://doi.org/10.1016/j.cell.2019.10.006
chicago: Schwayer, Cornelia, Shayan Shamipour, Kornelija Pranjic-Ferscha, Alexandra
Schauer, M Balda, M Tada, K Matter, and Carl-Philipp J Heisenberg. “Mechanosensation
of Tight Junctions Depends on ZO-1 Phase Separation and Flow.” Cell. Cell
Press, 2019. https://doi.org/10.1016/j.cell.2019.10.006.
ieee: C. Schwayer et al., “Mechanosensation of tight junctions depends on
ZO-1 phase separation and flow,” Cell, vol. 179, no. 4. Cell Press, p.
937–952.e18, 2019.
ista: Schwayer C, Shamipour S, Pranjic-Ferscha K, Schauer A, Balda M, Tada M, Matter
K, Heisenberg C-PJ. 2019. Mechanosensation of tight junctions depends on ZO-1
phase separation and flow. Cell. 179(4), 937–952.e18.
mla: Schwayer, Cornelia, et al. “Mechanosensation of Tight Junctions Depends on
ZO-1 Phase Separation and Flow.” Cell, vol. 179, no. 4, Cell Press, 2019,
p. 937–952.e18, doi:10.1016/j.cell.2019.10.006.
short: C. Schwayer, S. Shamipour, K. Pranjic-Ferscha, A. Schauer, M. Balda, M. Tada,
K. Matter, C.-P.J. Heisenberg, Cell 179 (2019) 937–952.e18.
date_created: 2019-11-12T12:51:06Z
date_published: 2019-10-31T00:00:00Z
date_updated: 2026-06-07T22:30:09Z
day: '31'
ddc:
- '570'
department:
- _id: CaHe
- _id: BjHo
doi: 10.1016/j.cell.2019.10.006
ec_funded: 1
external_id:
isi:
- '000493898000012'
pmid:
- '31675500'
file:
- access_level: open_access
checksum: 33dac4bb77ee630e2666e936b4d57980
content_type: application/pdf
creator: dernst
date_created: 2020-10-21T07:09:45Z
date_updated: 2020-10-21T07:09:45Z
file_id: '8684'
file_name: 2019_Cell_Schwayer_accepted.pdf
file_size: 8805878
relation: main_file
success: 1
file_date_updated: 2020-10-21T07:09:45Z
has_accepted_license: '1'
intvolume: ' 179'
isi: 1
issue: '4'
language:
- iso: eng
month: '10'
oa: 1
oa_version: Submitted Version
page: 937-952.e18
pmid: 1
project:
- _id: 260F1432-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '742573'
name: Interaction and feedback between cell mechanics and fate specification in
vertebrate gastrulation
publication: Cell
publication_identifier:
eissn:
- 1097-4172
issn:
- 0092-8674
publication_status: published
publisher: Cell Press
quality_controlled: '1'
related_material:
link:
- description: News auf IST Website
relation: press_release
url: https://ist.ac.at/en/news/biochemistry-meets-mechanics-the-sensitive-nature-of-cell-cell-contact-formation-in-embryo-development/
record:
- id: '7186'
relation: dissertation_contains
status: public
- id: '8350'
relation: dissertation_contains
status: public
scopus_import: '1'
status: public
title: Mechanosensation of tight junctions depends on ZO-1 phase separation and flow
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 179
year: '2019'
...
---
_id: '6486'
abstract:
- lang: eng
text: Based on a novel control scheme, where a steady modification of the streamwise
velocity profile leads to complete relaminarization of initially fully turbulent
pipe flow, we investigate the applicability and usefulness of custom-shaped honeycombs
for such control. The custom-shaped honeycombs are used as stationary flow management
devices which generate specific modifications of the streamwise velocity profile.
Stereoscopic particle image velocimetry and pressure drop measurements are used
to investigate and capture the development of the relaminarizing flow downstream
these devices. We compare the performance of straight (constant length across
the radius of the pipe) honeycombs with custom-shaped ones (variable length across
the radius) and try to determine the optimal shape for maximal relaminarization
at minimal pressure loss. The optimally modified streamwise velocity profile is
found to be M-shaped, and the maximum attainable Reynolds number for total relaminarization
is found to be of the order of 10,000. Consequently, the respective reduction
in skin friction downstream of the device is almost by a factor of 5. The break-even
point, where the additional pressure drop caused by the device is balanced by
the savings due to relaminarization and a net gain is obtained, corresponds to
a downstream stretch of distances as low as approximately 100 pipe diameters of
laminar flow.
acknowledged_ssus:
- _id: M-Shop
article_number: '111105'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Jakob
full_name: Kühnen, Jakob
id: 3A47AE32-F248-11E8-B48F-1D18A9856A87
last_name: Kühnen
orcid: 0000-0003-4312-0179
- first_name: Davide
full_name: Scarselli, Davide
id: 40315C30-F248-11E8-B48F-1D18A9856A87
last_name: Scarselli
orcid: 0000-0001-5227-4271
- first_name: Björn
full_name: Hof, Björn
id: 3A374330-F248-11E8-B48F-1D18A9856A87
last_name: Hof
orcid: 0000-0003-2057-2754
citation:
ama: Kühnen J, Scarselli D, Hof B. Relaminarization of pipe flow by means of 3D-printed
shaped honeycombs. Journal of Fluids Engineering. 2019;141(11). doi:10.1115/1.4043494
apa: Kühnen, J., Scarselli, D., & Hof, B. (2019). Relaminarization of pipe flow
by means of 3D-printed shaped honeycombs. Journal of Fluids Engineering.
ASME. https://doi.org/10.1115/1.4043494
chicago: Kühnen, Jakob, Davide Scarselli, and Björn Hof. “Relaminarization of Pipe
Flow by Means of 3D-Printed Shaped Honeycombs.” Journal of Fluids Engineering.
ASME, 2019. https://doi.org/10.1115/1.4043494.
ieee: J. Kühnen, D. Scarselli, and B. Hof, “Relaminarization of pipe flow by means
of 3D-printed shaped honeycombs,” Journal of Fluids Engineering, vol. 141,
no. 11. ASME, 2019.
ista: Kühnen J, Scarselli D, Hof B. 2019. Relaminarization of pipe flow by means
of 3D-printed shaped honeycombs. Journal of Fluids Engineering. 141(11), 111105.
mla: Kühnen, Jakob, et al. “Relaminarization of Pipe Flow by Means of 3D-Printed
Shaped Honeycombs.” Journal of Fluids Engineering, vol. 141, no. 11, 111105,
ASME, 2019, doi:10.1115/1.4043494.
short: J. Kühnen, D. Scarselli, B. Hof, Journal of Fluids Engineering 141 (2019).
date_created: 2019-05-26T21:59:13Z
date_published: 2019-11-01T00:00:00Z
date_updated: 2026-06-07T22:30:46Z
day: '01'
department:
- _id: BjHo
doi: 10.1115/1.4043494
ec_funded: 1
external_id:
arxiv:
- '1809.07625'
isi:
- '000487748600005'
intvolume: ' 141'
isi: 1
issue: '11'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1809.07625
month: '11'
oa: 1
oa_version: Preprint
project:
- _id: 25152F3A-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '306589'
name: Decoding the complexity of turbulence at its origin
publication: Journal of Fluids Engineering
publication_identifier:
eissn:
- 1528-901X
issn:
- 0098-2202
publication_status: published
publisher: ASME
quality_controlled: '1'
related_material:
record:
- id: '7258'
relation: dissertation_contains
status: public
scopus_import: '1'
status: public
title: Relaminarization of pipe flow by means of 3D-printed shaped honeycombs
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 141
year: '2019'
...
---
_id: '6228'
abstract:
- lang: eng
text: Following the recent observation that turbulent pipe flow can be relaminarised bya relatively simple modification of the mean velocity profile, we here carry out aquantitative experimental investigation of this phenomenon. Our study confirms thata flat velocity profile leads to a collapse of turbulence and in order to achieve theblunted profile shape, we employ a moving pipe segment that is briefly and rapidlyshifted in the streamwise direction. The relaminarisation threshold and the minimumshift length and speeds are determined as a function of Reynolds number. Althoughturbulence is still active after the acceleration phase, the modulated profile possessesa severely decreased lift-up potential as measured by transient growth. As shown,this results in an exponential decay of fluctuations and the flow relaminarises. Whilethis method can be easily applied at low to moderate flow speeds, the minimumstreamwise length over which the acceleration needs to act increases linearly with theReynolds number.
article_processing_charge: No
arxiv: 1
author:
- first_name: Davide
full_name: Scarselli, Davide
id: 40315C30-F248-11E8-B48F-1D18A9856A87
last_name: Scarselli
orcid: 0000-0001-5227-4271
- first_name: Jakob
full_name: Kühnen, Jakob
id: 3A47AE32-F248-11E8-B48F-1D18A9856A87
last_name: Kühnen
orcid: 0000-0003-4312-0179
- 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, Kühnen J, Hof B. Relaminarising pipe flow by wall movement. Journal
of Fluid Mechanics. 2019;867:934-948. doi:10.1017/jfm.2019.191
apa: Scarselli, D., Kühnen, J., & Hof, B. (2019). Relaminarising pipe flow by
wall movement. Journal of Fluid Mechanics. Cambridge University Press.
https://doi.org/10.1017/jfm.2019.191
chicago: Scarselli, Davide, Jakob Kühnen, and Björn Hof. “Relaminarising Pipe Flow
by Wall Movement.” Journal of Fluid Mechanics. Cambridge University Press,
2019. https://doi.org/10.1017/jfm.2019.191.
ieee: D. Scarselli, J. Kühnen, and B. Hof, “Relaminarising pipe flow by wall movement,”
Journal of Fluid Mechanics, vol. 867. Cambridge University Press, pp. 934–948,
2019.
ista: Scarselli D, Kühnen J, Hof B. 2019. Relaminarising pipe flow by wall movement.
Journal of Fluid Mechanics. 867, 934–948.
mla: Scarselli, Davide, et al. “Relaminarising Pipe Flow by Wall Movement.” Journal
of Fluid Mechanics, vol. 867, Cambridge University Press, 2019, pp. 934–48,
doi:10.1017/jfm.2019.191.
short: D. Scarselli, J. Kühnen, B. Hof, Journal of Fluid Mechanics 867 (2019) 934–948.
date_created: 2019-04-07T21:59:14Z
date_published: 2019-05-25T00:00:00Z
date_updated: 2026-06-07T22:30:46Z
day: '25'
department:
- _id: BjHo
doi: 10.1017/jfm.2019.191
ec_funded: 1
external_id:
arxiv:
- '1807.05357'
isi:
- '000462606100001'
intvolume: ' 867'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1807.05357
month: '05'
oa: 1
oa_version: Preprint
page: 934-948
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
publication: Journal of Fluid Mechanics
publication_identifier:
eissn:
- 1469-7645
issn:
- 0022-1120
publication_status: published
publisher: Cambridge University Press
quality_controlled: '1'
related_material:
link:
- relation: supplementary_material
url: https://doi.org/10.1017/jfm.2019.191
record:
- id: '7258'
relation: dissertation_contains
status: public
scopus_import: '1'
status: public
title: Relaminarising pipe flow by wall movement
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 867
year: '2019'
...
---
_id: '6189'
abstract:
- lang: eng
text: 'Suspended particles can alter the properties of fluids and in particular
also affect the transition fromlaminar to turbulent flow. An earlier study [Mataset
al.,Phys. Rev. Lett.90, 014501 (2003)] reported howthe subcritical (i.e., hysteretic)
transition to turbulent puffs is affected by the addition of particles. Here weshow
that in addition to this known transition, with increasing concentration a supercritical
(i.e.,continuous) transition to a globally fluctuating state is found. At the
same time the Newtonian-typetransition to puffs is delayed to larger Reynolds
numbers. At even higher concentration only the globallyfluctuating state is found.
The dynamics of particle laden flows are hence determined by two competinginstabilities
that give rise to three flow regimes: Newtonian-type turbulence at low, a particle
inducedglobally fluctuating state at high, and a coexistence state at intermediate
concentrations.'
article_number: '114502'
article_processing_charge: No
arxiv: 1
author:
- first_name: Nishchal
full_name: Agrawal, Nishchal
id: 469E6004-F248-11E8-B48F-1D18A9856A87
last_name: Agrawal
- first_name: George H
full_name: Choueiri, George H
id: 448BD5BC-F248-11E8-B48F-1D18A9856A87
last_name: Choueiri
- first_name: Björn
full_name: Hof, Björn
id: 3A374330-F248-11E8-B48F-1D18A9856A87
last_name: Hof
orcid: 0000-0003-2057-2754
citation:
ama: Agrawal N, Choueiri GH, Hof B. Transition to turbulence in particle laden flows.
Physical Review Letters. 2019;122(11). doi:10.1103/PhysRevLett.122.114502
apa: Agrawal, N., Choueiri, G. H., & Hof, B. (2019). Transition to turbulence
in particle laden flows. Physical Review Letters. American Physical Society.
https://doi.org/10.1103/PhysRevLett.122.114502
chicago: Agrawal, Nishchal, George H Choueiri, and Björn Hof. “Transition to Turbulence
in Particle Laden Flows.” Physical Review Letters. American Physical Society,
2019. https://doi.org/10.1103/PhysRevLett.122.114502.
ieee: N. Agrawal, G. H. Choueiri, and B. Hof, “Transition to turbulence in particle
laden flows,” Physical Review Letters, vol. 122, no. 11. American Physical
Society, 2019.
ista: Agrawal N, Choueiri GH, Hof B. 2019. Transition to turbulence in particle
laden flows. Physical Review Letters. 122(11), 114502.
mla: Agrawal, Nishchal, et al. “Transition to Turbulence in Particle Laden Flows.”
Physical Review Letters, vol. 122, no. 11, 114502, American Physical Society,
2019, doi:10.1103/PhysRevLett.122.114502.
short: N. Agrawal, G.H. Choueiri, B. Hof, Physical Review Letters 122 (2019).
date_created: 2019-03-31T21:59:12Z
date_published: 2019-03-22T00:00:00Z
date_updated: 2026-06-07T22:31:01Z
day: '22'
department:
- _id: BjHo
doi: 10.1103/PhysRevLett.122.114502
external_id:
arxiv:
- '1809.06358'
isi:
- '000461922000006'
pmid:
- '30951357'
intvolume: ' 122'
isi: 1
issue: '11'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1809.06358
month: '03'
oa: 1
oa_version: Preprint
pmid: 1
publication: Physical Review Letters
publication_identifier:
eissn:
- 1079-7114
issn:
- 0031-9007
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
related_material:
record:
- id: '9728'
relation: dissertation_contains
status: public
scopus_import: '1'
status: public
title: Transition to turbulence in particle laden flows
type: journal_article
user_id: ba8df636-2132-11f1-aed0-ed93e2281fdd
volume: 122
year: '2019'
...
---
_id: '291'
abstract:
- lang: eng
text: Over the past decade, the edge of chaos has proven to be a fruitful starting
point for investigations of shear flows when the laminar base flow is linearly
stable. Numerous computational studies of shear flows demonstrated the existence
of states that separate laminar and turbulent regions of the state space. In addition,
some studies determined invariant solutions that reside on this edge. In this
paper, we study the unstable manifold of one such solution with the aid of continuous
symmetry reduction, which we formulate here for the simultaneous quotiening of
axial and azimuthal symmetries. Upon our investigation of the unstable manifold,
we discover a previously unknown traveling-wave solution on the laminar-turbulent
boundary with a relatively complex structure. By means of low-dimensional projections,
we visualize different dynamical paths that connect these solutions to the turbulence.
Our numerical experiments demonstrate that the laminar-turbulent boundary exhibits
qualitatively different regions whose properties are influenced by the nearby
invariant solutions.
article_number: '054401'
article_processing_charge: No
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: Björn
full_name: Hof, Björn
id: 3A374330-F248-11E8-B48F-1D18A9856A87
last_name: Hof
orcid: 0000-0003-2057-2754
citation:
ama: Budanur NB, Hof B. Complexity of the laminar-turbulent boundary in pipe flow.
Physical Review Fluids. 2018;3(5). doi:10.1103/PhysRevFluids.3.054401
apa: Budanur, N. B., & Hof, B. (2018). Complexity of the laminar-turbulent boundary
in pipe flow. Physical Review Fluids. American Physical Society. https://doi.org/10.1103/PhysRevFluids.3.054401
chicago: Budanur, Nazmi B, and Björn Hof. “Complexity of the Laminar-Turbulent Boundary
in Pipe Flow.” Physical Review Fluids. American Physical Society, 2018.
https://doi.org/10.1103/PhysRevFluids.3.054401.
ieee: N. B. Budanur and B. Hof, “Complexity of the laminar-turbulent boundary in
pipe flow,” Physical Review Fluids, vol. 3, no. 5. American Physical Society,
2018.
ista: Budanur NB, Hof B. 2018. Complexity of the laminar-turbulent boundary in pipe
flow. Physical Review Fluids. 3(5), 054401.
mla: Budanur, Nazmi B., and Björn Hof. “Complexity of the Laminar-Turbulent Boundary
in Pipe Flow.” Physical Review Fluids, vol. 3, no. 5, 054401, American
Physical Society, 2018, doi:10.1103/PhysRevFluids.3.054401.
short: N.B. Budanur, B. Hof, Physical Review Fluids 3 (2018).
date_created: 2018-12-11T11:45:39Z
date_published: 2018-05-30T00:00:00Z
date_updated: 2023-09-11T12:45:44Z
day: '30'
department:
- _id: BjHo
doi: 10.1103/PhysRevFluids.3.054401
external_id:
arxiv:
- '1802.01918'
isi:
- '000433426200001'
intvolume: ' 3'
isi: 1
issue: '5'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1802.01918
month: '05'
oa: 1
oa_version: Preprint
publication: Physical Review Fluids
publication_status: published
publisher: American Physical Society
publist_id: '7590'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Complexity of the laminar-turbulent boundary in pipe flow
type: journal_article
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 3
year: '2018'
...
---
_id: '328'
abstract:
- lang: eng
text: The drag of turbulent flows can be drastically decreased by adding small amounts
of high molecular weight polymers. While drag reduction initially increases with
polymer concentration, it eventually saturates to what is known as the maximum
drag reduction (MDR) asymptote; this asymptote is generally attributed to the
dynamics being reduced to a marginal yet persistent state of subdued turbulent
motion. Contrary to this accepted view, we show that, for an appropriate choice
of parameters, polymers can reduce the drag beyond the suggested asymptotic limit,
eliminating turbulence and giving way to laminar flow. At higher polymer concentrations,
however, the laminar state becomes unstable, resulting in a fluctuating flow with
the characteristic drag of the MDR asymptote. Our findings indicate that the asymptotic
state is hence dynamically disconnected from ordinary turbulence. © 2018 American
Physical Society.
acknowledged_ssus:
- _id: SSU
acknowledgement: The authors thank Philipp Maier and the IST Austria workshop for
their dedicated technical support.
article_number: '124501'
article_processing_charge: No
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: 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, Hof B. Exceeding the asymptotic limit of polymer
drag reduction. Physical Review Letters. 2018;120(12). doi:10.1103/PhysRevLett.120.124501
apa: Choueiri, G. H., Lopez Alonso, J. M., & Hof, B. (2018). Exceeding the asymptotic
limit of polymer drag reduction. Physical Review Letters. American Physical
Society. https://doi.org/10.1103/PhysRevLett.120.124501
chicago: Choueiri, George H, Jose M Lopez Alonso, and Björn Hof. “Exceeding the
Asymptotic Limit of Polymer Drag Reduction.” Physical Review Letters. American
Physical Society, 2018. https://doi.org/10.1103/PhysRevLett.120.124501.
ieee: G. H. Choueiri, J. M. Lopez Alonso, and B. Hof, “Exceeding the asymptotic
limit of polymer drag reduction,” Physical Review Letters, vol. 120, no.
12. American Physical Society, 2018.
ista: Choueiri GH, Lopez Alonso JM, Hof B. 2018. Exceeding the asymptotic limit
of polymer drag reduction. Physical Review Letters. 120(12), 124501.
mla: Choueiri, George H., et al. “Exceeding the Asymptotic Limit of Polymer Drag
Reduction.” Physical Review Letters, vol. 120, no. 12, 124501, American
Physical Society, 2018, doi:10.1103/PhysRevLett.120.124501.
short: G.H. Choueiri, J.M. Lopez Alonso, B. Hof, Physical Review Letters 120 (2018).
corr_author: '1'
date_created: 2018-12-11T11:45:51Z
date_published: 2018-03-19T00:00:00Z
date_updated: 2025-06-04T07:52:00Z
day: '19'
department:
- _id: BjHo
doi: 10.1103/PhysRevLett.120.124501
ec_funded: 1
external_id:
arxiv:
- '1703.06271'
isi:
- '000427804000005'
intvolume: ' 120'
isi: 1
issue: '12'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1703.06271
month: '03'
oa: 1
oa_version: Preprint
project:
- _id: 25681D80-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '291734'
name: International IST Postdoc Fellowship Programme
- _id: 25152F3A-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '306589'
name: Decoding the complexity of turbulence at its origin
publication: Physical Review Letters
publication_status: published
publisher: American Physical Society
publist_id: '7537'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Exceeding the asymptotic limit of polymer drag reduction
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 120
year: '2018'
...