Spectral Analysis of Generic Rocket Wake Flows with Cold and Hot Exhaust Jets

Abstract

The dynamic motions of the wake flow fields of a generic rocket launcher geometry at Mach 0.8, interacting with a supersonic exhaust jet at different stagnation conditions, ranging from 288 to 919 K are addressed in this work. They were analyzed regarding its spectral content by means of high-speed Schlieren imaging and unsteady chamber pressure measurements. The spectral analysis captured the typical wake flow frequencies and their characteristic mode shapes of the cross-flapping and swinging motions of the ambient shear layer at SrD = 0.19 and 0.35. At certain conditions, a strong amplification of the swinging motion was observed, which is probably governed by a coupling of the dynamic wake flow modes and the acoustic chamber properties.