Recent advances and current challenges for DSMC

The current status of the direct simulation Monte Carlo (or DSMC) method is reviewed with particular emphasis on its range of validity, the extent of its validation against experiment, and the new molecular models that have been developed in the context of DSMC modelling. The growing number of DSMC applications to the study of flow instabilities are discussed and results are presented for new calculations of unsteady axially symmetric and three-dimensional Taylor-Couette flows. The axially symmetric cases exhibit a transition at a critical Reynolds number from an eventual steady laminar flow to a permanently unsteady flow.