Numerical Simulation of Gross Structure of Turbulent Plane Mixing Layer by Discrete-vortex Model

Abstract

A discrete-vortex model is used to simulate a turbulent plane mixing layer. The vorticity in the mixing layer is partitioned into a number of vorticity blods which are again replaced by inviscid discrete vortices with an inner structure. It is found that random walks of appropriate variance should be superposed on the motion of the vortices in order to obtain the time-averaged velocity and turbulent quantities consistent with experiments. The random walks are assumed to simulate very roughly the diffusion of vorticity by turbulent transport. The potential field of application of the present model and its limitations are also discussed.