Turbulent flow over a backward-facing step, perturbed periodically by alternative blowing∕suction through a thin slit (0.05H width) situated at the step edge, was studied computationally using (LES) large eddy simulation, (DES) detached eddy simulation, and (T-RANS) transient Reynolds-averaged Navier–Stokes techniques. The flow configuration considered (ReH=UcHν=3700) has been investigated experimentally by Yoshioka et al. (1 2). The periodic blowing∕suction with zero net mass flux is governed by a sinusoidal law: ve=0.3Ucsin(2πfet), Uc being the centerline velocity in the inlet channel. Perturbation frequencies fe corresponding to the Strouhal numbers St=0.08, 0.19, and 0.30 were investigated (St=feHUc). The experimental observation that the perturbation frequency St=0.19 represents the most effective case, that is the case with the minimum reattachment length, was confirmed by all computational methods. However, the closest agreement with experiment (the reattachment length reduction of 28.3% compared to the unperturbed case) was obtained with LES (24.5%) and DES (35%), whereas the T-RANS computations showed a weaker sensitivity to the perturbation: 5.9% when using the Spalart–Allmaras model and 12.9% using the k-ω SST model.

1.
Yoshioka
,
S.
,
Obi
,
S.
, and
Masuda
,
S.
, 2001, “
Organized Vortex Motion in Periodically Perturbed Separated Flow Over a Backward-Facing Step
,”
Int. J. Heat Fluid Flow
0142-727X,
22
, pp.
301
307
.
2.
Yoshioka
,
S.
,
Obi
,
S.
, and
Masuda
,
S.
, 2001, “
Turbulence Statistics of Periodically Perturbed Separated Flow Over Backward-Facing Step
,”
Int. J. Heat Fluid Flow
0142-727X,
22
, pp.
393
401
.
3.
Seifert
,
A.
, and
Pack
,
L. G.
, 1999, “
Oscillatory Control of Separation at High Reynolds Numbers
,”
AIAA J.
0001-1452,
37
, pp.
1062
1071
.
4.
Seifert
,
A.
, and
Pack
,
L. G.
, 2002, “
Active Flow Separation Control on Wall-Mounted Hump at High Reynolds Numbers
,”
AIAA J.
0001-1452,
40
, pp.
1363
1372
.
5.
Chun
,
K. B.
, and
Sung
,
H. J.
, 1996, “
Control of Turbulent Separated Flow Over a Backward-Facing Step
,”
Exp. Fluids
0723-4864,
21
, pp.
417
426
.
6.
Jin
,
S.
,
Choi
,
H.
,
Kim
,
S.
,
Yul
,
Y.-J.
, and
Kim
,
S.-R.
, 2001, “
An Experimental Study of Turbulent Backward-Facing Step Flow Under Two-Frequency Forcing
,”
Exp. Heat Transfer
0891-6152,
Fluid Mechanics and Thermodynamics
,
Celata
et al.
, eds.,
Edizioni ETS
, Pisa, pp.
1933
1938
.
7.
Khosla
,
P. K.
, and
Rubin
,
S. G.
, 1974, “
A Diagonally Dominant Second-Order Accurate Implicit Scheme
,”
Comput. Fluids
0045-7930,
2
, pp.
207
209
.
8.
Spalart
,
P. R.
, and
Allmaras
,
S. R.
, 1994, “
A One-Equation Turbulence Model for Aerodynamic Flows
,”
La Rech. A’erospatiale
,
1
, pp.
5
21
.
9.
Menter
,
F. R.
, 1994, “
Zonal Two-Equation k-ω Turbulence Model for Aerodynamic Flows
,” AIAA P
1993
2906
.
10.
Jakirlić
,
S.
,
Jester-Zürker
,
R.
, and
Tropea
,
C.
, 2002, “
9th ERCOFTAC∕IAHR∕COST Workshop on Refined Turbulence Modelling
,”
ERCOFTAC Bulletin
, December,
55
, pp.
36
43
.
11.
Stawiarski
,
K.
, and
Hanjalic
,
K.
, 2002, “
A Two-Scale Second-Moment One-Pont Turbulence Closure
,”
Engineering Turbulence Modelling and Experiment
,
5
,
W.
Rodi
and
N.
Fueyo
, eds.,
Elsevier Science
, pp.
97
106
.
12.
Spalart
,
P. R.
,
Jou
,
W.-H.
,
Strelets
,
M.
, and
Allmaras
,
S. R.
, 1997, “
Comments on the Feasibility of LES for Wings and on Hybrid RANS∕LES Approach
,”
Proc. First AFOSR International Conference on DNS and LES
,
Ruston
, LA, USA.
13.
Travin
,
A.
,
Shur
,
M.
,
Strelets
,
M.
, and
Spalart
,
P. R.
, 2002, “
Physical and Numerical Upgrades in the Detached-Eddy Simulation of Complex Turbulence Flows
,” In
Fluid Mechanics and Its Application: Advances in LES of Complex Flows
,
R.
Friedrich
and
W.
Rodi
, eds.,
65
,
Kluwer Academic Publisher
, pp.
239
254
.
14.
Moin
,
P.
, and
Kim
,
J.
, 1982, “
Numerical Investigation of Turbulent Channel Flow
,”
J. Fluid Mech.
0022-1120,
118
, pp.
341
377
.
15.
Akselvoll
,
K.
, and
Moin
,
P.
, 1993, “
Large Eddy Simulation of a Backward Facing Step Flow
,”
Engineering Turbulence Modeling and Experiment
,
2
,
W.
Rodi
and
F.
Martelli
, eds.,
Elsevier Science Ltd.
, pp.
303
313
.
16.
Kim
,
J.
,
Moin
,
P.
, and
Moser
,
R.
, 1987, “
Turbulence Statistics in Fully Developed Channel Flow at the Low Reynolds Number
,”
J. Fluid Mech.
0022-1120,
177
, pp.
133
166
.
17.
Leschziner
,
M. A.
, 2001, “
At the Crossroads of Turbulence Modelling and Simulation: Opportunities and Challenges
,”
Proc. Eighth IAHR International Symposium on Flow Modelling and Turbulence Measurements
,
Tokyo
, Japan, December 4–6.
18.
Obi
,
S.
, 2002 (private communication).
19.
Kasagi
,
N.
, and
Matsunaga
,
A.
, 1995, “
Three-Dimensional Particle-Tracking Velocity Measurements of Turbulence Statistics and Energy Budget in a Backward-Facing Step Flow
,”
Int. J. Heat Fluid Flow
0142-727X,
16
, pp.
477
485
.
20.
Dejoan
,
A.
,
Jang
,
Y.-J.
, and
Leschziner
,
M.
, 2004, “
LES and Unsteady RANS Computations for a Periodically-Perturbed Separated Flow Over a Backward-Facing Step
,”
Proc. ASME Heat Transfer∕Fluids Engineering Summer Conference
,
Charlotte
, NC, USA, July 11–15.
21.
Arnal
,
M.
, and
Friedrich
,
R.
, 1993, “
Large-Eddy Simulation of a Turbulent Flow With Separation
,”
Turbulent Shear Flows
,
8
,
F.
Durst
et al.
, eds.,
Springer Verlag
, pp.
169
187
.
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