A 2D NAVIER-STOKES METHOD FOR UNSTEADY COMPRESSIBLE FLOW CALCULATIONSON MOVING MESHES

A moving mesh method for the computation of compressible viscous flow past deforming and moving aerofoils is described. It is based on a wel l established time-marching finite-volume scheme, which has been widel y used for steady compressible flows. An implicit realtime discretisat ion is used and the equations are integrated via a dual-time scheme. T his involves the introduction of derivatives of a fictitious pseudo ti me. The solution at each real-time step involves seeking solutions whi ch are steady-state solutions in pseudo time. This approach decouples the stability and accuracy limitations of the scheme and permits large real-time steps to be chosen. Also well-proven convergence accelerati on techniques developed for steady flows such as local-time stepping, residual averaging and multigrid may be used in the pseudo-time steppi ng scheme without compromising real-time accuracy. A sequence of body- conforming grids and corresponding grid speeds is required, where the inner and outer boundaries of the grid move independently. The require d grids and speeds are found using a transfinite interpolation techniq ue. Applications of the method to external compressible flows are show n, including results from a parallel version of the computer program.