Direct simulation Monte Carlo calculation of a jet interaction experiment

Abstract

This study deals with the development of a methodology for numerically simulating the interaction of a reaction control system (RCS) jet with a low-density external flow. A European Space Agency experiment was chosen as a test case, since it provided experimental data that could validate some of the numerical results. The initial approach was to focus on several subproblems having direct relevance to the full interaction problem. This enabled different numerical methods to be investigated separately and validated for each part of the interaction problem. In this manner, the best methodology for solving the full interaction problem was developed. The subproblems considered in this study included typical RCS nozzle and plume flows, a flat plate at zero incidence, and the flow past the experimental test model without the control jet firing. Once these calculations were completed, a simulation was performed of the test model with the control jet operating at the experimental density. The results from this final simulation were compared with experimental measurements. Nomenclature = reference diameter, m = Knudsen number at nozzle throat = Knudsen number at nozzle lip = Mach number = number density, molecules/m3 = freestream number density, molecules/m3 = pressure, Pa = Reynolds number T^ef = reference temperature, K 7waii = temperature of nozzle wall T^ = freestream temperature, K X, Y, Z = Cartesian body coordinates p , - density, kg/m3 Poo = freestream density, kg/m3 Kn\ip M