Abstract

This talk presents an analytic solution for the sound generated by rotor-stator interaction for aerofoils with small (but non-zero) camber and thickness. The interaction is modelled as an unsteady gust incident on an infinite rectilinear cascade of staggered aerofoils in background steady uniform flow at small angles of attack using Rapid Distortion Theory. The solution significantly extends previous analytical work that is restricted to flat plates or only calculates the far-upstream radiation, and can give insight into the role played by blade geometry on the acoustic field both upstream and downstream of the cascade. The steady solution for the mean flow is required in order to solve the unsteady interaction equation governing the acoustic field, which is performed using the Wiener-Hopf technique. Results for the unsteady loading are presented and compared with existing results for flat plates to investigate the effects of realistic geometry.