Cross-statistical and wavelet analysis of velocity and wall-pressure fields in jet-surface interaction

In the present work the installation effects of a flat-plate close to a low-speed incompressible jet are analyzed. An experimental study involving simultaneous velocity measurements of the aerodynamic field of the jet and wall pressure measurements on the surface was carried out. The plate was installed tangentially to the nozzle axis at different radial distances. The change on the mean and fluctuating velocity field due to the presence of the surface was characterized by point-wise hot wire anemometer measurements. Wall pressure fluctuations induced by the jet were measured by a cavity mounted microphone array in the stream-wise direction. Cross-statistics between velocity and wall pressure signals was char- acterized in the time domain, addressing the effect of the radial distance of the flat-plate from the jet as a function of the stream-wise and cross-wise positions of the probes. A conditional averaging procedure based on wavelet transform was applied to the database in order to educe velocity signatures characterizing the coherent structures underlying the physics of the jet-surface interaction and inducing the high-energy wall pressure events.