| The hypersonic viscous flow past cavities are simulated by solving the time dependent compressible Navier-Stokes equations. An implicit finite volume numerical algorithm based on the LU-SGS scheme, with a Newton-like subiteration procedure, was developed to perform the time-accurate computations. The Newton-like subiteration procedure is implemented to yield second-order temporal accuracy. The effects of the subiteration procedure as well as the approximations made in the derivation of the original scheme are examined. The algorithm is highly vectorizable and robust resulting in computational rates comparable to those of explicit schemes. Accurate viscous results of the unsteady hypersonic flow fields are obtained. The effects of Reynolds number and cavity dimensions in two-, and three-dimensional flows are investigated. In the computations large vortex structures, which adversely affect the cavity flow characteristics, are observed at the rear of the cavity. A self-sustained oscillatory motion occurs within the cavity over a range of Reynolds number and cavity dimensions. Transition from open to closed cavity flows are investigated. The comparison of the computations with available experimental data, in terms of time mean static pressure, heat transfer, and Mach number show good agreement. |
