A Periodically Perturbed Backward-Facing Step Flow by Means of LES, DES and T-RANS: An Example of Flow Separation Control

Turbulent flow over a backward-facing step, perturbed periodically by alternative blowing/suction through a thin slit (0.05 H 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 (Re H =U c H/v=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: v e =0.3U c sin(2πf e t), U c being the centerline velocity in the inlet channel. Perturbation frequencies f e corresponding to the Strouhal numbers St=0.08, 0.19, and 0.30 were investigated (St=f e H/U c )

[1]  H. Sung,et al.  Control of turbulent separated flow over a backward-facing step by local forcing , 1996 .

[2]  Christopher L. Rumsey,et al.  Assessment of two-equation turbulence models for transonic flows , 1994 .

[3]  P. Moin,et al.  Numerical investigation of turbulent channel flow , 1981, Journal of Fluid Mechanics.

[4]  Shinnosuke Obi,et al.  Organized vortex motion in periodically perturbed turbulent separated flow over a backward-facing step , 2001 .

[5]  Shinnosuke Obi,et al.  Turbulence statistics of periodically perturbed separated flow over backward-facing step , 2001 .

[6]  S. G. Rubin,et al.  A diagonally dominant second-order accurate implicit scheme , 1974 .

[7]  Michael A. Leschziner,et al.  AT THE CROSSROADS OF TURBULENCE MODELLING AND SIMULATION: OPPORTUNITIES AND CHALLENGES , 2002 .

[8]  A. Seifert,et al.  Active Flow Separation Control on Wall-Mounted Hump at High Reynolds Numbers , 2002 .

[9]  A. Seifert,et al.  Oscillatory Control of Separation at High Reynolds Numbers , 1999 .

[10]  P. Moin,et al.  Turbulence statistics in fully developed channel flow at low Reynolds number , 1987, Journal of Fluid Mechanics.

[11]  P. Spalart.  A One-Equation Turbulence Model for Aerodynamic Flows , 1992 .

[12]  N. Kasagi,et al.  Three-dimensional particle-tracking velocimetry measurement of turbulence statistics and energy budget in a backward-facing step flow , 1995 .

[13]  P. Spalart.  Comments on the feasibility of LES for wings, and on a hybrid RANS/LES approach , 1997 .