Monte Carlo Simulation of Radiation in Hypersonic Flows.

摘要

Radiation is generated in hypersonic flows of missiles. Depending on the flight altitude, the gas dynamics may be modeled by continuum or kinetic simulation techniques At high altitude, kinetic methods are more physically accurate, but continuum methods are more numerically efficient. In an attempt to utilize the best of both approaches, we are undertaking the development of a hybrid continuum-kinetic method for high altitude hypersonic flows. Ultimately, such a method will provide the ability to obtain physically accurate and numerically efficient predictions of the radiation generated by hypersonic missiles The development of this hybrid method involves two important steps: (1) determination in a flow field of when to switch between the continuum and kinetic methods (a so-called continuum breakdown parameter); and (2) smooth and physically accurate communication of data between the continuum and kinetic methods. This report describes a first version of such a hybrid code that is applied to a hypersonic flow over a two-dimensional wedge. The preliminary results are encouraging although they also point to areas where the method requires improvement.