An experimental investigation of the wall pressure field induced by a low and moderate mach numbers jet on a tangential flat plate

In this work an experimental analysis of the wall pressure field generated by the interaction between a subsonic jet and a flat plate parallel to the nozzle axis is performed. The analysis is the continuation of previous studies carried out by the same authors on the interaction between a jet and a flat plate in an incompressible jet facility. In the present work a similar installed configuration has been analyzed exploiting a compressible jet facility in order to address the effect of the transition from incompressible to low/moderate compressible flow conditions. The pressure footprint on the flat plate was measured in both the streamwise and spanwise directions through a flush-mounted microphone array for different radial distances of the surface from the jet. Wall pressure fluctuations have been characterized in terms of statistical and spectral quantities. Implications for modelling of the wall pressure fluctuations are considered by the application of the Corcos’ model to the coherence functions in both the streamwise and spanwise directions. Specifically, the Corcos’ model was verified for all the jet flow velocities, the increase of the jet Mach number having the effect to enhance the jet flow development over the plate and to speed up the approach of a quasi-equilibrium turbulent boundary layer.