An Investigation of Type IV Shock Interaction Over a Blunt Body with Forward-Facing Cavity

Abstract

Shock wave interaction occurs in many external and internal flow fields around hypersonic vehicles. The type IV shock interaction is one of the six types of shock interactions categorized by Edney [1] and is characterized by a supersonic jet embedded with the surrounding subsonic flow. It receives the most attention because it creates the most complex flow pattern and severe heating problem. Substantial experimental [2–4] and computational [5–8] research efforts have been made to study such type of shock interaction. Unsteady oscillations with typical frequencies of 3–10 kHz were first observed by Holden et al. [3]. With the same conditions as that of the experiments [3] however, Gaitonde and Shang [5] performed a numerical study with a modified Steger–Warming scheme and revealed that the dominant frequency was about 32 kHz. Zhong [7], Chu, and Lu [8] solved the Navier–Stokes equations using high-order schemes to analyze the characteristics of the unsteady type IV shock interaction. Unfortunately, the frequencies of their calculations were still far from that of the experiment. In addition, there has been an interesting speculation that introducing an opposing jet [9] or a forward-facing cavity [10] at the nose region of a blunt body may reduce the drag and aerothermal loads. However, it needs to be pointed out that the introduction of a cavity or an opposing jet in the stagnation-point region will inevitably bring some new flow features especially when shock interaction occurs.