Artificial viscosity models for vortex and particle methods

The analysis of the truncation error produced by particle methods leads to artificial viscosity schemes. For vortex methods, they can be seen as eddy viscosity models, with anisotropic non-linear diffusion tensors. Numerical experiments on decaying incompressible 2D turbulence illustrate the efficiency of the method, and in particular the fact that the diffusion stops acting in large coherent eddies. For compressible flows, this approach allows us to understand the oscillations produced by particle methods and to derive new artificial viscosity schemes. 11 refs., 6 figs