An analytical model for the prediction of airfoil cascade-turbulence interaction noise

A analytical method is presented in this paper to compute the turbulence-cascade interaction noise with real airfoil geometry. Two key assumptions are made: 1) the property of sound generated by an airfoil only depends on the local mean flow and vortical gust; 2) each airfoil only scatters the sound waves radiated from other airfoils. A proposed analytical solution for the noise generated by a real airfoil can be utilised to compute the acoustic response to the oncoming vortical gusts. The analytical solution was developed based on a generalised Prandtl-Glauert transformation to account for the non-uniform mean flow effect. As for the interaction between the cascade airfoils, the sound scattering is resolved using the high-efficiency boundary element method. This abstract presents the principle steps in the proposed analytical model. Initial results for zero stagger angle flat plate cascades are computed, and match well with the high order numerical simulation results, giving us the confidence with the validities of the assumptions made in the analytical model.