Book Description

The analysis extends Cheng's theory of the hypersonic, thin, viscous shock layer to include effects of foreign gas injection. It is found that the effectiveness of mass transfer in reducing stagnation region heating rates and skin friction increases with an increasing hypersonic viscous similarity parameter, k squared, for a given injection parameter B. In general, the lighter injectant gas is more effective than the heavier injectant gas in reducing both skin friction and heat transfer. The values of the blow-off point for zero skin friction occur at approximately kB = 0.5 and 0.385 for helium and hydrogen, respectively. The lighter injectant gas also tends to thicken the shock layer for a given magnitude of the injection parameter, B, but such effects diminish for high values of k squared and appear to approach an asymptotic limit for a given gas at a given injectant parameter B as k squared approaches infinity. For sufficiently low Reynolds numbers, the effects of mass transfer on both heat transfer and skin friction disappear. For helium and hydrogen injections, it appears that a simple correction of the molecular weight ratio raised to a constant exponent of 1/2 gives a reasonable correlation with air-to-air injection at the stagnation point. (Author).