---
_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: 2024-03-25T23:30:20Z
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:
- '14697645'
issn:
- '00221120'
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: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 867
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: 2024-03-25T23:30:20Z
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:
- 1528901X
issn:
- '00982202'
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: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 141
year: '2019'
...
---
_id: '461'
abstract:
- lang: eng
text: Turbulence is the major cause of friction losses in transport processes and
it is responsible for a drastic drag increase in flows over bounding surfaces.
While much effort is invested into developing ways to control and reduce turbulence
intensities, so far no methods exist to altogether eliminate turbulence if velocities
are sufficiently large. We demonstrate for pipe flow that appropriate distortions
to the velocity profile lead to a complete collapse of turbulence and subsequently
friction losses are reduced by as much as 90%. Counterintuitively, the return
to laminar motion is accomplished by initially increasing turbulence intensities
or by transiently amplifying wall shear. Since neither the Reynolds number nor
the shear stresses decrease (the latter often increase), these measures are not
indicative of turbulence collapse. Instead, an amplification mechanism measuring
the interaction between eddies and the mean shear is found to set a threshold
below which turbulence is suppressed beyond recovery.
acknowledgement: We acknowledge the European Research Council under the European Union’s
Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement 306589, the European
Research Council (ERC) under the European Union’s Horizon 2020 research and innovation
programme (grant agreement no. 737549) and the Deutsche Forschungsgemeinschaft (Project
No. FOR 1182) for financial support. We thank our technician P. Maier for providing
highly valuable ideas and greatly supporting us in all technical aspects. We thank
M. Schaner for technical drawings, construction and design. We thank M. Schwegel
for a Matlab code to post-process experimental data.
article_processing_charge: No
author:
- first_name: Jakob
full_name: Kühnen, Jakob
id: 3A47AE32-F248-11E8-B48F-1D18A9856A87
last_name: Kühnen
orcid: 0000-0003-4312-0179
- first_name: Baofang
full_name: Song, Baofang
last_name: Song
- first_name: Davide
full_name: Scarselli, Davide
id: 40315C30-F248-11E8-B48F-1D18A9856A87
last_name: Scarselli
orcid: 0000-0001-5227-4271
- first_name: Nazmi B
full_name: Budanur, Nazmi B
id: 3EA1010E-F248-11E8-B48F-1D18A9856A87
last_name: Budanur
orcid: 0000-0003-0423-5010
- first_name: Michael
full_name: Riedl, Michael
id: 3BE60946-F248-11E8-B48F-1D18A9856A87
last_name: Riedl
orcid: 0000-0003-4844-6311
- first_name: Ashley
full_name: Willis, Ashley
last_name: Willis
- 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: Kühnen J, Song B, Scarselli D, et al. Destabilizing turbulence in pipe flow.
Nature Physics. 2018;14:386-390. doi:10.1038/s41567-017-0018-3
apa: Kühnen, J., Song, B., Scarselli, D., Budanur, N. B., Riedl, M., Willis, A.,
… Hof, B. (2018). Destabilizing turbulence in pipe flow. Nature Physics.
Nature Publishing Group. https://doi.org/10.1038/s41567-017-0018-3
chicago: Kühnen, Jakob, Baofang Song, Davide Scarselli, Nazmi B Budanur, Michael
Riedl, Ashley Willis, Marc Avila, and Björn Hof. “Destabilizing Turbulence in
Pipe Flow.” Nature Physics. Nature Publishing Group, 2018. https://doi.org/10.1038/s41567-017-0018-3.
ieee: J. Kühnen et al., “Destabilizing turbulence in pipe flow,” Nature
Physics, vol. 14. Nature Publishing Group, pp. 386–390, 2018.
ista: Kühnen J, Song B, Scarselli D, Budanur NB, Riedl M, Willis A, Avila M, Hof
B. 2018. Destabilizing turbulence in pipe flow. Nature Physics. 14, 386–390.
mla: Kühnen, Jakob, et al. “Destabilizing Turbulence in Pipe Flow.” Nature Physics,
vol. 14, Nature Publishing Group, 2018, pp. 386–90, doi:10.1038/s41567-017-0018-3.
short: J. Kühnen, B. Song, D. Scarselli, N.B. Budanur, M. Riedl, A. Willis, M. Avila,
B. Hof, Nature Physics 14 (2018) 386–390.
date_created: 2018-12-11T11:46:36Z
date_published: 2018-01-08T00:00:00Z
date_updated: 2024-03-25T23:30:20Z
day: '08'
department:
- _id: BjHo
doi: 10.1038/s41567-017-0018-3
ec_funded: 1
external_id:
isi:
- '000429434100020'
intvolume: ' 14'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1711.06543
month: '01'
oa: 1
oa_version: Preprint
page: 386-390
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: Nature Physics
publication_status: published
publisher: Nature Publishing Group
publist_id: '7360'
quality_controlled: '1'
related_material:
record:
- id: '12726'
relation: dissertation_contains
status: public
- id: '14530'
relation: dissertation_contains
status: public
- id: '7258'
relation: dissertation_contains
status: public
scopus_import: '1'
status: public
title: Destabilizing turbulence in pipe flow
type: journal_article
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 14
year: '2018'
...
---
_id: '422'
abstract:
- lang: eng
text: We show that a rather simple, steady modification of the streamwise velocity
profile in a pipe can lead to a complete collapse of turbulence and the flow fully
relaminarizes. Two different devices, a stationary obstacle (inset) and a device
which injects fluid through an annular gap close to the wall, are used to control
the flow. Both devices modify the streamwise velocity profile such that the flow
in the center of the pipe is decelerated and the flow in the near wall region
is accelerated. We present measurements with stereoscopic particle image velocimetry
to investigate and capture the development of the relaminarizing flow downstream
these devices and the specific circumstances responsible for relaminarization.
We find total relaminarization up to Reynolds numbers of 6000, where the skin
friction in the far downstream distance is reduced by a factor of 3.4 due to relaminarization.
In a smooth straight pipe the flow remains completely laminar downstream of the
control. Furthermore, we show that transient (temporary) relaminarization in a
spatially confined region right downstream the devices occurs also at much higher
Reynolds numbers, accompanied by a significant local skin friction drag reduction.
The underlying physical mechanism of relaminarization is attributed to a weakening
of the near-wall turbulence production cycle.
article_processing_charge: Yes (via OA deal)
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: Markus
full_name: Schaner, Markus
id: 316CE034-F248-11E8-B48F-1D18A9856A87
last_name: Schaner
- 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, Schaner M, Hof B. Relaminarization by steady modification
of the streamwise velocity profile in a pipe. Flow Turbulence and Combustion.
2018;100(4):919-942. doi:10.1007/s10494-018-9896-4
apa: Kühnen, J., Scarselli, D., Schaner, M., & Hof, B. (2018). Relaminarization
by steady modification of the streamwise velocity profile in a pipe. Flow Turbulence
and Combustion. Springer. https://doi.org/10.1007/s10494-018-9896-4
chicago: Kühnen, Jakob, Davide Scarselli, Markus Schaner, and Björn Hof. “Relaminarization
by Steady Modification of the Streamwise Velocity Profile in a Pipe.” Flow
Turbulence and Combustion. Springer, 2018. https://doi.org/10.1007/s10494-018-9896-4.
ieee: J. Kühnen, D. Scarselli, M. Schaner, and B. Hof, “Relaminarization by steady
modification of the streamwise velocity profile in a pipe,” Flow Turbulence
and Combustion, vol. 100, no. 4. Springer, pp. 919–942, 2018.
ista: Kühnen J, Scarselli D, Schaner M, Hof B. 2018. Relaminarization by steady
modification of the streamwise velocity profile in a pipe. Flow Turbulence and
Combustion. 100(4), 919–942.
mla: Kühnen, Jakob, et al. “Relaminarization by Steady Modification of the Streamwise
Velocity Profile in a Pipe.” Flow Turbulence and Combustion, vol. 100,
no. 4, Springer, 2018, pp. 919–42, doi:10.1007/s10494-018-9896-4.
short: J. Kühnen, D. Scarselli, M. Schaner, B. Hof, Flow Turbulence and Combustion
100 (2018) 919–942.
date_created: 2018-12-11T11:46:23Z
date_published: 2018-01-01T00:00:00Z
date_updated: 2024-03-25T23:30:20Z
day: '01'
ddc:
- '530'
department:
- _id: BjHo
doi: 10.1007/s10494-018-9896-4
ec_funded: 1
external_id:
isi:
- '000433113900004'
file:
- access_level: open_access
checksum: d7c0bade150faabca150b0a9986e60ca
content_type: application/pdf
creator: dernst
date_created: 2018-12-17T15:52:37Z
date_updated: 2020-07-14T12:46:25Z
file_id: '5717'
file_name: 2018_FlowTurbulenceCombust_Kuehnen.pdf
file_size: 2210020
relation: main_file
file_date_updated: 2020-07-14T12:46:25Z
has_accepted_license: '1'
intvolume: ' 100'
isi: 1
issue: '4'
language:
- iso: eng
month: '01'
oa: 1
oa_version: Published Version
page: 919 - 942
project:
- _id: 25152F3A-B435-11E9-9278-68D0E5697425
call_identifier: FP7
grant_number: '306589'
name: Decoding the complexity of turbulence at its origin
publication: Flow Turbulence and Combustion
publication_status: published
publisher: Springer
publist_id: '7401'
quality_controlled: '1'
related_material:
record:
- id: '7258'
relation: dissertation_contains
status: public
scopus_import: '1'
status: public
title: Relaminarization by steady modification of the streamwise velocity profile
in a pipe
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 100
year: '2018'
...
---
_id: '1837'
abstract:
- lang: eng
text: 'Transition to turbulence in straight pipes occurs in spite of the linear
stability of the laminar Hagen-Poiseuille flow if both the amplitude of flow perturbations
and the Reynolds number Re exceed a minimum threshold (subcritical transition).
As the pipe curvature increases, centrifugal effects become important, modifying
the basic flow as well as the most unstable linear modes. If the curvature (tube-to-coiling
diameter d/D) is sufficiently large, a Hopf bifurcation (supercritical instability)
is encountered before turbulence can be excited (subcritical instability). We
trace the instability thresholds in the Re - d/D parameter space in the range
0.01 ≤ d/D\ ≤ 0.1 by means of laser-Doppler velocimetry and determine the point
where the subcritical and supercritical instabilities meet. Two different experimental
set-ups are used: a closed system where the pipe forms an axisymmetric torus and
an open system employing a helical pipe. Implications for the measurement of friction
factors in curved pipes are discussed.'
article_number: R3
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: P
full_name: Braunshier, P
last_name: Braunshier
- first_name: M
full_name: Schwegel, M
last_name: Schwegel
- first_name: Hendrik
full_name: Kuhlmann, Hendrik
last_name: Kuhlmann
- 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, Braunshier P, Schwegel M, Kuhlmann H, Hof B. Subcritical versus supercritical
transition to turbulence in curved pipes. Journal of Fluid Mechanics. 2015;770(5).
doi:10.1017/jfm.2015.184
apa: Kühnen, J., Braunshier, P., Schwegel, M., Kuhlmann, H., & Hof, B. (2015).
Subcritical versus supercritical transition to turbulence in curved pipes. Journal
of Fluid Mechanics. Cambridge University Press. https://doi.org/10.1017/jfm.2015.184
chicago: Kühnen, Jakob, P Braunshier, M Schwegel, Hendrik Kuhlmann, and Björn Hof.
“Subcritical versus Supercritical Transition to Turbulence in Curved Pipes.” Journal
of Fluid Mechanics. Cambridge University Press, 2015. https://doi.org/10.1017/jfm.2015.184.
ieee: J. Kühnen, P. Braunshier, M. Schwegel, H. Kuhlmann, and B. Hof, “Subcritical
versus supercritical transition to turbulence in curved pipes,” Journal of
Fluid Mechanics, vol. 770, no. 5. Cambridge University Press, 2015.
ista: Kühnen J, Braunshier P, Schwegel M, Kuhlmann H, Hof B. 2015. Subcritical versus
supercritical transition to turbulence in curved pipes. Journal of Fluid Mechanics.
770(5), R3.
mla: Kühnen, Jakob, et al. “Subcritical versus Supercritical Transition to Turbulence
in Curved Pipes.” Journal of Fluid Mechanics, vol. 770, no. 5, R3, Cambridge
University Press, 2015, doi:10.1017/jfm.2015.184.
short: J. Kühnen, P. Braunshier, M. Schwegel, H. Kuhlmann, B. Hof, Journal of Fluid
Mechanics 770 (2015).
date_created: 2018-12-11T11:54:17Z
date_published: 2015-04-08T00:00:00Z
date_updated: 2021-01-12T06:53:31Z
day: '08'
department:
- _id: BjHo
doi: 10.1017/jfm.2015.184
ec_funded: 1
external_id:
arxiv:
- '1508.06559'
intvolume: ' 770'
issue: '5'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1508.06559
month: '04'
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 Fluid Mechanics
publication_status: published
publisher: Cambridge University Press
publist_id: '5265'
quality_controlled: '1'
scopus_import: 1
status: public
title: Subcritical versus supercritical transition to turbulence in curved pipes
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 770
year: '2015'
...
---
_id: '2050'
abstract:
- lang: eng
text: The flow instability and further transition to turbulence in a toroidal pipe
(torus) with curvature ratio (tube-to-coiling diameter) 0.049 is investigated
experimentally. The flow inside the toroidal pipe is driven by a steel sphere
fitted to the inner pipe diameter. The sphere is moved with constant azimuthal
velocity from outside the torus by a moving magnet. The experiment is designed
to investigate curved pipe flow by optical measurement techniques. Using stereoscopic
particle image velocimetry, laser Doppler velocimetry and pressure drop measurements,
the flow is measured for Reynolds numbers ranging from 1000 to 15 000. Time- and
space-resolved velocity fields are obtained and analysed. The steady axisymmetric
basic flow is strongly influenced by centrifugal effects. On an increase of the
Reynolds number we find a sequence of bifurcations. For Re=4075±2% a supercritical
bifurcation to an oscillatory flow is found in which waves travel in the streamwise
direction with a phase velocity slightly faster than the mean flow. The oscillatory
flow is superseded by a presumably quasi-periodic flow at a further increase of
the Reynolds number before turbulence sets in. The results are found to be compatible,
in general, with earlier experimental and numerical investigations on transition
to turbulence in helical and curved pipes. However, important aspects of the bifurcation
scenario differ considerably.
article_processing_charge: No
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: Markus
full_name: Holzner, Markus
last_name: Holzner
- first_name: Björn
full_name: Hof, Björn
id: 3A374330-F248-11E8-B48F-1D18A9856A87
last_name: Hof
orcid: 0000-0003-2057-2754
- first_name: Hendrik
full_name: Kuhlmann, Hendrik
last_name: Kuhlmann
citation:
ama: Kühnen J, Holzner M, Hof B, Kuhlmann H. Experimental investigation of transitional
flow in a toroidal pipe. Journal of Fluid Mechanics. 2014;738:463-491.
doi:10.1017/jfm.2013.603
apa: Kühnen, J., Holzner, M., Hof, B., & Kuhlmann, H. (2014). Experimental investigation
of transitional flow in a toroidal pipe. Journal of Fluid Mechanics. Cambridge
University Press. https://doi.org/10.1017/jfm.2013.603
chicago: Kühnen, Jakob, Markus Holzner, Björn Hof, and Hendrik Kuhlmann. “Experimental
Investigation of Transitional Flow in a Toroidal Pipe.” Journal of Fluid Mechanics.
Cambridge University Press, 2014. https://doi.org/10.1017/jfm.2013.603.
ieee: J. Kühnen, M. Holzner, B. Hof, and H. Kuhlmann, “Experimental investigation
of transitional flow in a toroidal pipe,” Journal of Fluid Mechanics, vol.
738. Cambridge University Press, pp. 463–491, 2014.
ista: Kühnen J, Holzner M, Hof B, Kuhlmann H. 2014. Experimental investigation of
transitional flow in a toroidal pipe. Journal of Fluid Mechanics. 738, 463–491.
mla: Kühnen, Jakob, et al. “Experimental Investigation of Transitional Flow in a
Toroidal Pipe.” Journal of Fluid Mechanics, vol. 738, Cambridge University
Press, 2014, pp. 463–91, doi:10.1017/jfm.2013.603.
short: J. Kühnen, M. Holzner, B. Hof, H. Kuhlmann, Journal of Fluid Mechanics 738
(2014) 463–491.
date_created: 2018-12-11T11:55:25Z
date_published: 2014-01-10T00:00:00Z
date_updated: 2021-01-12T06:54:59Z
day: '10'
department:
- _id: BjHo
doi: 10.1017/jfm.2013.603
external_id:
arxiv:
- '1508.06546'
intvolume: ' 738'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1508.06546
month: '01'
oa: 1
oa_version: Submitted Version
page: 463 - 491
publication: Journal of Fluid Mechanics
publication_status: published
publisher: Cambridge University Press
publist_id: '5001'
quality_controlled: '1'
scopus_import: 1
status: public
title: Experimental investigation of transitional flow in a toroidal pipe
type: journal_article
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 738
year: '2014'
...