COUPLING BOLTZMANN AND NAVIER-STOKES EQUATIONS BY HALF FLUXES

We introduce an adaptative coupling of the Boltzmann and Navier-Stokes equations to compute hypersonic flows around a vehicle at high altitu de. The coupling is achieved by matching half fluxes at the interface of the Boltzmann and Navier-Stokes domains. The domains are determined automatically by computing local kinetic residuals on a preliminary N avier-Stokes solution. Our method is developed here for monoatomic gas es. Different numerical results illustrate its validity and limits. (C ) 1997 Academic Press.