Acoustic Wave Generation from Two-Dimensional Supersonic Inviscid Jet Impinging on Inclined Plate

Abstract

This study numerically analyzes the interaction between a two-dimensional supersonic inviscid jet impinging on an inclined flat plate and the inlet disturbance using a simplified model depicting the rocket launch acoustic noise. The jet is a correctly expanded Mach 1.8 supersonic jet, the plate angle is 45 deg, and the nozzle–plate distance is five times the nozzle height. Three types of acoustic waves, namely, 1) a wave propagating normal to the wall, 2) a wave propagating upstream from the top and bottom of the plate shock, and 3) a wave propagating omnidirectionally from the first tail shock, which are consistent with those in Akamine’s experiment, are observed. The acoustic wave generation mechanisms are 1) a rapid growth of pressure amplitude downstream of the plate shock, 2) a deformation of the plate shock accompanied with the oscillation of the stagnation pressure, and 3) a cyclic pressure fluctuation due to the cyclic change in the shock structure near the first tail shock. Although the flowfield studied is simple compared with the actual rocket launch flow environment, the mechanism revealed in this study will provide a useful insight into understanding the sound generation mechanism in a complicated three-dimensional turbulent impinging jet.