Numerical simulation of turbulent flow over a backward facing step using partially averaged Navier-Stokes method

This paper presents some key features of partially averaged Navier-Stokes (PANS) method in the simulation of turbulent flow over a backward facing step at Re_h = 5100. Both fixed and spatially variable values for the unresolved-to-total ratio of kinetic energy (f_k) are adopted in the present PANS simulations. Different model parameters relevant to PANS have been assessed. Detached eddy simulation (DES) is also adopted and the results from DES are compared in detail with PANS and the available experimental data. Variable f_k PANS gives overall acceptable predictions but it is slightly less accurate than DES. The defects of PANS simulation with fixed f_k throughout the entire computational domain are highlighted in this investigation. An improved step is to introduce variable f_k to ensure the near-wall Reynolds averaged Navier-Stokes (RANS) solution. This paper provides encouraging results for PANS simulations of this wall-bounded flow involving separation.