The elucidation of mechanism of Local Sound Pressure Levels increase phenomenon

Abstract

In spacecraft system acoustic tests, one often sees local pressure increase in the narrow gap between spacecraft primal structure and components facing toward the fairing wall. This acoustical environment load to the components differs from that the components were tested alone and the flight acoustic environment may not be actually simulated in the ground testing. In this paper, in order to clarify the mechanism and evaluate this pressure increase, basic experiment including acoustic testing and vibration modal survey is employed. It is found that the main reason of the phenomenon is dominated by the acoustic cavity on the appropriate boundary condition rather than structure vibration. Boundary element method is used to analysis the phenomenon and comparison of analysis and experiment results are carried out.