On the Wall Pressure Fluctuations induced by a Supersonic Jet over the Wing pressure side

Abstract

Supersonic jet wing integrated configurations are expected to be relatively louder than subsonic installed configurations, increasing the wall pressure load transmitted inside the fuselage and stressing the wing/fuselage panels with very energetic and frequency localized supersonic effects. In this framework, a model-scale experimental investigation of an installed jet-wing configuration has been performed using a supersonic convergent-divergent nozzle interacting with a wing generated by a NACA4415 airfoil. The measurements have been carried out in the semi-anechoic chamber of the "G.Guj"Fluid Dynamic laboratory at the University Roma Tre. Wall pressure fluctuations are acquired at different axial locations in stream-wise and span-wise directions. Measurements are repeated for different wing radial positions and by varying the NPR between 2.2 and 2.6, thus exploring both over-expanded and under-expanded jet flow conditions. The flow features that characterize the different flow regimes were caught using the Background Oriented Schlieren (BOS) technique. Fluctuating pressure data, acquired with flush-mounted pressure transducers, were analysed in the frequency domain, considering a Fourier-based approach. A comparison of results obtained with an infinite flat plate has been used to highlight effects generated by the discontinuity related to the trailing edge.