Trailing-edge noise prediction using large-eddy simulation and acoustic analogy

The filtered Navier-Stokes equations are used to perform the large eddy simulation of the unsteady incompressible flow around the blunt trailing edge of a thick hat plate. The computed how exhibits a three-dimensional vortex shedding mechanism. The frequency domain of this mechanism is in agreement with experiments and theory. In that frequency domain normalized wall pressure levels are favorably compared to spectra measured at the blunted trailing edge of an airfoil. The far field radiated noise is first computed via Curie's formulation, the solution of Lighthill's equation for hows embedding solid bodies. Then the theory developed by Ffowes Williams and Hall is considered. This formulation expresses the noise generated by turbulence passing over the edge of an infinite halfplane. The suitability of this theory to the case for a thick prate is discussed. The normalized spectra of the radiated noise predicted by both methods are compared, in the frequency domain of the vortex-shedding mechanism, to airfoil noise measurements in an anechoic facility.