A Unified Flow Solver (UFS) combining Direct Numerical Solution (DNS) of the Boltzmann kinetic equation with kinetic schemes of the continuum gas dynamics was tested for blunt body flows. The UFS capabilities for computing heat flux over blunt bodies are tested for supersonic and hypersonic flows. The heat flux simulation has been attempted by several Cartesian mesh users in the past and is known to be a problem to evaluate heat flux. We consider Mach 3 and Mach 10 monatomic gas flows over a 2D cylinder, Mach 3 and the low enthalpy Mach 16 molecular gas flows over an axisymmetric blunt body. We demonstrate the various factors affecting the computation of heat flux, the major factors being, (1) Cartesian mesh refinement issues, (2) the size of kinetic domain (with reference to the Boltzmann solver) near the surface, (3) using continuum solver with viscosity near the surface, and (4) boundary cutting issues. In this paper we show how the UFS offers an improvement over other existing Cartesian mesh solvers due to its Boltzmann/kinetic solver capabilities.
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