A new diffusion procedure for vortex methods (Q1924860)

A method is proposed for simulating diffusion in vortex methods for two-dimensional incompressible flows. The method resolves length scales up to the spacing of the vortices. The grid-free nature of vortex methods is fully retained and the distribution of the vortices can be irregular. The method is based on exchanging a conserved quantity between arbitrary computational points. To test the method, the decay processes of a single point vortex and of a counterrotating pair of point vortices are computed. Current limitations of the method are discussed.