The Analysis of Underexpanded Jet Flows for Hypersonic Aerodynamic Experiments in Vacuum Chambers
نویسندگان
چکیده
Underexpanded jets have become widely used in studies of rarefied-gas flows [1][3] and aerodynamics of hypersonic probes in wind tunnels [4]-[7]. The objective of the present study is to analyze shapes and flow parameters in internal regions of hypersonic underexpanded viscous jets, and to apply the jet theory to hypersonic studies. Analytical solutions [7] are used for estimating internal flow parameters. The role of kinetic effects in the expanding flows of Ar and He is evaluated using the direct simulation Monte-Carlo (DSMC) technique [8]. Rotational relaxation is analyzed using quantum concepts [9], [10]. Aerodynamic characteristics of wedges, disks, and plates are studied in experiments with hypersonic underexpanded jets of He, Ar, N2, and CO2, and compared with the DSMC calculations [11]. Similarity parameters and fundamental aerodynamics laws are discussed.
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