斜め平板に衝突する超音速噴流と渦の干渉から生じる音響現象

抄録

Interaction between a rocket exhaust plume and a flame deflector causes intense acoustic waves during a launch vehicle liftoff. The prediction and the reduction of these waves are quite important for the safe transportation of the payloads. Past studies discussing acoustic phenomena of a supersonic axisymmetric jet impinging on an inclined flat plate reported three types of acoustic waves, and also indicated that interaction between the large scale disturbance at the shear layer and the flowfield can be attributable to the acoustic wave generation. However, the generation mechanism of the acoustic wave perpendicular to the plate has not been clarified. In this study, a supersonic impinging planer jet overlayed with an isolated disturbance is simulated numerically and the resulting acoustic waves are discussed in detail. The numerical result shows three acoustic waves similar to those observed in Akamine et al.'s experiment. These waves seem to be generated from the interaction between the disturbance convected over the shear layer and the near-wall shock structures.