Direct numerical simulation of turbulent mixing in shear flows

Abstract

This article considers one of the simplest shear flows–ID time-dependent plane mixing layer. Under certain conditions, many more complicated flows are similar to it: timeindependent plane mixing layer, initial portion of plane and round jets, initial mixing phase in cylindrical vortex, etc. This application was previously studied in a 2D approximation. In this computation the turbulence was treated as the result of random perturbations initially applied to the interface of two flows. Numerical simulation used a 2D EGAK code. The computational results were interpreted using the version of semi-empirical turbulent theory with isotropic Reynolds tensor (model 1). This article continues the studies by Bakhrakh; in addition, a similar approach is implemented based on 3D simulation with the TREK method. The data interpretation uses the version of semi-empirical theory with and without Reynolds tensor anisotropy (models 1 and 2, respectively).