VORTEX SIMULATION OF TURBULENT MIXING LAYERS

We present here a brief survey of vortex-dynamical simulations of the plane mixing layer using different forms of vortex elements. Points an d blobs, which have been widely used in the past, suffer from irregula r evolution of the vortex sheet approximating the shear layer, and the rather long time-averaging required to obtain meaningful statistics. A technique recently proposed by the authors, using vortex arcs or she et elements, has been found to be helpful in avoiding these difficulti es. In particular, this technique avoids the singularity in induced ve locity associated with point vortex techniques, and is therefore in no need of any form of the ''desingularization'' that is often introduce d in the latter. New results for excited mixing layers using the vorte x sheet element model are presented, and are shown to be in good agree ment with experimental observations.