Parallel Navier–Stokes simulations for high speed compressible flow past arbitrary geometries using FLASH

• Extensions made to enable Navier–Stokes simulation for arbitrary bodies.
• Parallel performance studied in pure MPI and hybrid MPI-OpenMP modes.
• Navier–Stokes simulations for several hypersonic test cases carried out.

We report extensions to the FLASH code to enable high-speed compressible viscous flow simulation past arbitrary two- and three-dimensional stationary bodies. The body shape is embedded in a block-structured Cartesian adaptive mesh refinement grid by implementing appropriate computer graphics algorithms. A high mesh refinement level is required for an accurate body shape representation which results in large grid sizes especially for three-dimensional simulations. Simulations are done in parallel on IBM Blue Gene/Q computing system on which the code performance has been assessed in both pure MPI and hybrid MPI-OpenMP modes. We also implement appropriate wall boundary conditions in FLASH to model viscous-wall effects. Navier–Stokes (NS) solutions for various two-dimensional test cases like a shock–boundary layer interaction problem as well as for hypersonic flow past blunted cone–cylinder–flare and double-cone geometries are shown. Three dimensional NS simulations of micro vortex generators employed in hypersonic flow control have also been carried out and the computed results have been found to be consistent with experimental results.