A COMPARISON OF THE CAPABILITIES OF ONE-EQUATION AND 2-EQUATION DIFFERENTIAL MODELS OF TURBULENCE IN APPLICATION TO SEPARATED AND ATTACHED FLOWS IN A CHANNEL WITH FORWARD-FACING STEP

A comparative numerical study is performed of the capabilities of thre e recently proposed differential models of turbulence based on one [2, 3] and two [4] equations in application to separated and attached flo ws. The previous publication [1] was concerned with flows formed in ch annels with backward-facing steps, while in this study we treat the fl ow formed in a channel with a forward-facing step (with abrupt contrac tion). In contrast to flows in a channel with a backward-facing step, the dow treated by us includes two recirculation zones, one of which h as a wandering separation point. This fact considerably complicates th e description of flow and imposes more rigid requirements on the turbu lence model. The computational results are compared with experimental data [5] and with the computation results obtained within a version of the kappa-epsilon turbulence model. As in the case of flows in a chan nel with a backward-facing step, one-equation turbulence models [2, 3] are found to offer considerable advantages over the kappa-epsilon mod el in terms of both computation efficiency and precision.