Extension of the Euler/Navier-Stokes Code CEVCATS to Inviscid Nonequilibrium Flows.

Abstract

The numerical simulation of hypersonic reacting 3D flows is one of the key tools for the design of reentry vehicles. Earlier design work, however, has precluded the extensive use of 3D flow simulations with nonequilibrium chemistry because of the long computation times. Recent progress in the development of solution algorithms and the speed up of supercomputers have now improved the situation drastically. Efficient Navier-Stokes simulations of complex hypersonic 3D flows have recently been demonstrated using the assumptions of calorically perfect gas or reacting air in thermochemical equilibrium. With convergence acceleration techniques such as multigrid implemented on vector computers with a performance of about 1GFLOP/s computation times are now in the order of 1-2 hours for solutions involving 1 million grid points. The extension of one of these fast 3D codes CEVCATS to nonequilibriumreacting flows is the subject of the work. In the first step, the code is extended to treat multiple species equations and the thermodynamics describing inviscid flow. The new code is validated by grid convergence studies and comparisons with numerical results ofthe DLR NSHYP code. Beside the numerical results, a brief descriptionis given concerning the implementation of the code on a NEC-SX3 vector computer.