This project will develop software to simulate flows and configurations to give insight into the dynamic mixing processes involved in wakes, jets and shear layers. In particular numerical code will be developed for flows of importance in aerodynamics. By basing the family of models for two-dimensional viscous, incompressible flows on a Lagrangian formulation of fluid motion, the dynamics of mixing can be studied as a function of the Reynolds number. Viscosity is introduced by allowing the vorticity to diffuse as in the exact self-similar solution to the Navier-Stokes equations describing the viscous growth of an isolated vortex core.