Investigation of Unsteady Edney Type IV and VII Shock–Shock Interactions

Abstract

Edney type IV and type VII shock–shock interactions are complex hypersonic flow phenomena. They are characterized by a supersonic jet that reaches far into the flowfield. An experimental investigation of the inner jet structure is difficult, especially in cases where the jet is subject to high-frequency unsteady movements. The present paper provides insight into the jet structure and its movement by means of a highly resolved computational fluid dynamics analysis in thermochemical nonequilibrium that significantly exceeds the resolution of existing publications. Simulations of an Edney type IV interaction in nitrogen flow are presented. Advanced adaptation strategies allow for the identification and analysis of the mechanisms of the jet unsteadiness, resulting in a new classification of the unsteady flowfield behavior with respect to the periodic jet movement. This classification is based not only on wall quantities, but also on the core flowfield. The computations are supplemented by a grid sensitivity study. The second configuration is an Edney type VII interaction. This shock–shock interaction type was observed and defined in nitrogen flow by Yamamoto et al (Numerical Investigation of Shock/Vortex Interaction in Hypersonic Thermochemical Nonequilibrium Flow, Journal of Spacecraft and Rockets, Vol. 36, No. 2, 1999, pp. 240–246. The present results demonstrate that this interaction may also be observed in carbon-dioxide-dominated flow with a gas composition similar to the Martian atmosphere. The results provide insight into the jet structure of this less known interaction.