Trailing edge noise prediction from measured surface pressures

A comprehensive experimental investigation of trailing edge noise is reported for the case of a two-dimensional airfoil embedded in a uniform low Mach number flow. The Reynolds number is high and the boundary layer is fully turbulent. Parameters include angle of attack, flow velocity, and trailing edge bluntness. By using a coherent output power method, the trailing edge noise spectra and directivity (including forward speed effects) are quantitatively determined. Statistics of the pressure field beneath the turbulent boundary layer are defined in detail. The scattered pressure field (primarily incompressive) very near the trailing edge is measured and successfully modeled by extending existing theory. This helps establish the edge condition (of pertinence to the Kutta condition) which in turn determines the solution for the sound field in this study. By using a statistical model of the turbulent boundary layer pressure field, trailing edge noise is well predicted.