Separated flow behind a backward-facing step. Part II. Experimental and   numerical investigation of a turbulent flow
  We present the results of an experimental and numerical investigation of a turbulent flow over a backward-facing step in a channel. Experimental data are visualized using a Particle Image Velocimetry (PIV) device. As a mathematical model we used quasi-hydrodynamic (QHD) equations. We have carried out numerical modeling of the flow for three configurations that were also studied experimentally. The computed flow proved to be non-stationary. The averaged flow in the separation zone is in a good agreement with the experimental data. 
T. G. Elizarova, E. V. Shilnikov, R. Weber, J. Hureau