On flux-extrapolation at supersonic outflow boundaries Original Research Article

One way of imposing boundary conditions for the Navier–Stokes equations at artificial supersonic outflow boundaries is to use flux-extrapolation. This procedure is analyzed and compared with variable-extrapolation both for the semi-discrete and continuous problem using the Laplace transform technique. It is shown that flux-extrapolation leads to a loss of accuracy and an extra time growth. The numerical experiments support the analytical results.