Shock detachment from cones in a relaxing gas

Abstract

Measurements of the shock stand-off distance on cones of various base diameters in carbon dioxide and nitrogen flows with dissociative relaxation show that the detachment process occurs more gradually with relaxation than in a perfect gas, as the cone semi-angle is increased. This is in agreement with a prediction which is made on the basis of the behaviour of the sonic surface in the flow field. The phenomenon is similar to that observed previously with wedge flow but shows interesting effects peculiar to the cone flow. The cone experiments also eliminate the end effect and permit easy variation of the relaxation rate parameter without changing the gas. Perfect-gas argon experiments provide a convenient check.