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NONEQUILIBRIUM FLOW BEHIND STRONG SHOCK WAVES IN A DISSOCIATED AMBIENT
DOUGLAS AIRCRAFT CO INC SANTA MONICA CALIF
A theoretical study of effects of free stream dissociation on the nonequilibrium gas properties behind shock waves is described. The analysis is based on a set of oblique shock relations which are generalized to include an arbitrary degree of nonequilibrium vibration, dissociation or ionization ahead of andor behind the shock front. The frozen and equilibrium post-shock gas properties in air vs the ambient atom mass fraction and dissociation energy are presented at shock velocites ranging from 15,000 to 30,000 fps for normal and oblique hypersonic shock waves. Some of the potential effects of predissociation on the intervening relaxation process are briefly examined. Comparison is made with the properties behind geometrically-similar shock waves in a perfect undissociated ambient gas, independently of the preshock chemical history, for either the same shock velocity or the same total enthalpy. Significant changes in the post-shock density ratio, temperature, dissociation and ionization can occur if 10 or more of the total energy is tied up in preshock dissociation. Sharp reductions in the usual differences between the frozen and equilibrium properties associated with endothermic post-shock relaxation are observed when 50 or more of the total enthalpy is in preshock dissociation. Author