Flat-Faced Leading-Edge Effects in Low-Density Hypersonic Wedge Flow

摘要

A numerical study was performed to determine the upstream effects of leading-edge thickness on the rarefied hypersonic flow over truncated wedges at zero angle of attack. The simulations were performed by using the direct simulation Monte Carlo (DSMC) method. A method that has demonstrated excellent comparisons with flight- and ground-test data, it properly accounts for nonequilibrium aspects of the flow that arise near the leading edge, which are especially important at high Mach numbers. Some significant differences between sharp and blunt leading edges were noted on the flowfield structure and on the aerodynamic surface quantities. It was found that the upstream effects have a different influence on the stagnation streamline properties ahead of the leading edges depending on the leading-edge Knudsen number. Interesting features observed in the surface fluxes showed that small leading-edge thickness, compared to the freestream mean free path, has important effects on high-Mach-number leading-edge flows. Also, effects on the skin-friction coefficient, pressure coefficient, and heat-transfer coefficient on the wedge are presented as a function of thickness Knudsen number.