Abstract
This study considers the relationship between the time-averaged and phase-averaged flow fields in turbulent backward-facing step flow under the influence of periodic perturbation. Attempts are made to clarify the interaction between organized vortex motion and turbulence statistics such as Reynolds stress. The velocity fields are measured using a particle imaging velocimeter (PIV) for three selected perturbation frequencies, one corresponding to the most effective frequency in terms of the reduction of reattachment length, one below it and another above it. The evolution of organized vortex motion due to the imposed perturbation is found remarkable except for the case of perturbation at the highest frequency, at which the organized motion dissipates so quickly behind the step that the flow is not altered. At the most effective perturbation frequency, the regions of large Reynolds stress appear as a result of strong stretching between successive vortices caused by the perturbation. It is concluded that the change in the mean velocity field due to the organized fluid motion alters the production rate of Reynolds stress, which is a key effect of the perturbation on turbulent separated flow.
| Original language | English |
|---|---|
| Pages (from-to) | 301-307 |
| Number of pages | 7 |
| Journal | International Journal of Heat and Fluid Flow |
| Volume | 22 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - 2001 Jun |
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Keywords
- Backward-facing step
- Flow separation
- Particle imaging velocimeter
- Periodic perturbation
- Turbulence control
- Unsteady flow
ASJC Scopus subject areas
- Fluid Flow and Transfer Processes
- Mechanical Engineering
Cite this
Organized vortex motion in periodically perturbed turbulent separated flow over a backward-facing step. / Yoshioka, Shuya; Obi, Shinnosuke; Masuda, Shigeaki.
In: International Journal of Heat and Fluid Flow, Vol. 22, No. 3, 06.2001, p. 301-307.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Organized vortex motion in periodically perturbed turbulent separated flow over a backward-facing step
AU - Yoshioka, Shuya
AU - Obi, Shinnosuke
AU - Masuda, Shigeaki
PY - 2001/6
Y1 - 2001/6
N2 - This study considers the relationship between the time-averaged and phase-averaged flow fields in turbulent backward-facing step flow under the influence of periodic perturbation. Attempts are made to clarify the interaction between organized vortex motion and turbulence statistics such as Reynolds stress. The velocity fields are measured using a particle imaging velocimeter (PIV) for three selected perturbation frequencies, one corresponding to the most effective frequency in terms of the reduction of reattachment length, one below it and another above it. The evolution of organized vortex motion due to the imposed perturbation is found remarkable except for the case of perturbation at the highest frequency, at which the organized motion dissipates so quickly behind the step that the flow is not altered. At the most effective perturbation frequency, the regions of large Reynolds stress appear as a result of strong stretching between successive vortices caused by the perturbation. It is concluded that the change in the mean velocity field due to the organized fluid motion alters the production rate of Reynolds stress, which is a key effect of the perturbation on turbulent separated flow.
AB - This study considers the relationship between the time-averaged and phase-averaged flow fields in turbulent backward-facing step flow under the influence of periodic perturbation. Attempts are made to clarify the interaction between organized vortex motion and turbulence statistics such as Reynolds stress. The velocity fields are measured using a particle imaging velocimeter (PIV) for three selected perturbation frequencies, one corresponding to the most effective frequency in terms of the reduction of reattachment length, one below it and another above it. The evolution of organized vortex motion due to the imposed perturbation is found remarkable except for the case of perturbation at the highest frequency, at which the organized motion dissipates so quickly behind the step that the flow is not altered. At the most effective perturbation frequency, the regions of large Reynolds stress appear as a result of strong stretching between successive vortices caused by the perturbation. It is concluded that the change in the mean velocity field due to the organized fluid motion alters the production rate of Reynolds stress, which is a key effect of the perturbation on turbulent separated flow.
KW - Backward-facing step
KW - Flow separation
KW - Particle imaging velocimeter
KW - Periodic perturbation
KW - Turbulence control
KW - Unsteady flow
UR - http://www.scopus.com/inward/record.url?scp=0035371064&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0035371064&partnerID=8YFLogxK
U2 - 10.1016/S0142-727X(01)00092-3
DO - 10.1016/S0142-727X(01)00092-3
M3 - Article
AN - SCOPUS:0035371064
VL - 22
SP - 301
EP - 307
JO - International Journal of Heat and Fluid Flow
JF - International Journal of Heat and Fluid Flow
SN - 0142-727X
IS - 3
ER -