Effects of Burst in boundary layer on Oscillations of Pseudo-Shock waves

1989 Fiscal Year Final Research Report Summary

• Project/Area Number: 63550140
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: Fluid engineering
• Research Institution: Kyushu University
• Principal Investigator: MOCHIZUKI Hiroaki Kyushu University, Graduate School of Eng.Sciences, Research Associate, 総合理工学研究科, 助手 (70038058)
• Project Period (FY): 1988 – 1989
• Keywords: Supersonic Flow / Pseudo-Shock Waves / Boundary Layer / Interaction / Oscillation / Burst

Research Abstract

Pressure oscillations in a pseudo-shock waves, which generates by interacting with a boundary layer, are affected by pressure variation, which may regard as burst propagating from the boundary layer before the pseudo-shock waves. The effects of the burst on the oscillation of the pseudo-shock waves can be confirmed from maximum amplitude of the pressure oscillation at the first-shock position. The locations of the peaks in the streamwise distribution showing the maximum amplitude of pressure oscillations measured on the tube axis lie downstream from the positions of shock waves constituting the pseudo-shock waves. Also, the maximum pressure oscillation occurs in the neighborhood of the position where the flow acceleration downstream of the first-shock wave is over and the flow deceleration upstream of the second-shock waves begins. The correlations of the wall pressure oscillation at the first-shock wave with the pressure oscillations on the tube axis in the pseudo-shock waves takes two values, plus value for the pressure oscillations at locations in the flow acceleration regions and minus one for them at locations in the flow deceleration regions. It was clarified that the oscillation phenomena of the pseudo-shock waves could be affected by the boundary layer just upstream of the first-shock wave and the mechanism of the pseudo-shock waves.