Wall pressure fluctuations beneath hypersonic boundary layer over plate

Wall pressure fluctuations beneath a boundary layer are the main cause of structural vibration for hypersonic aircraft. To accurately predict the load environment of pressure fluctuations, a measurement in a hypersonic wind tunnel was carried out to investigate the characteristics of wall pressure fluctuations generated by different flow types. In the measurement, a linear sensor array was used to record the signal, and the beamforming algorithm was adopted to identify the spatial correlation of wall pressure fluctuations. The investigation discussed the main characteristics of the convective modes and acoustic modes for wall pressure fluctuations under different flow conditions, consisting of laminar flow, a transition, and fully developed turbulence. Two typical disturbances were found, both of which depend on the flow type and always reach their peak values during the transition period. Finally, a method was proposed to identify the acoustic modes and convective modes, and then an error analysis was performed.