Analysis of experimental unsteady wall pressure data from a jet installed above a semi-finite plate

Abstract

An investigation into the installation noise from a semi-finite flat plate next to a jet was performed. The experiment was carried out in the ISVR's anechoic Doak Laboratory, at the University of Southampton, using wall pressure transducers flush mounted over the plate surface and a far-field microphone array. In order to reproduce a setup representative of a real scaled jet-wing configuration the plate trailing edge was located at three nozzle exit diameters axially downstream of the jet exhaust. The radial position of the plate was varied from 0.76 to 1.50, nozzle exit diameters from the jet axis to the plate surface. The jet Mach number was also varied from 0.3 up to 0.9. The wall pressure transducers were positioned in the streamwise direction parallel to the jet centerline on the plate surface, including one position upstream of the nozzle exhaust. The pressure transducers in the spanwise direction were positioned close to the plate trailing edge. Data analyses were performed using multivariate statistical quantities in the time and frequency domains. Furthermore, application of the wavelet transform has been chosen to understand the relative contribution of turbulent boundary layer and jet shear layer pressure fields on the scattered far-field noise. Wall pressure data will be also correlated with the far field signals illustrating the propagation effects of the detected wall pressure signatures.