Leading edge noise from thick foils in turbulent flows

The prediction of dipole sound from the diffraction of turbulence by the leading edge of a rigid foil is made using acoustic analogies for homogeneous flows with and without mean shear. The Green’s function accounts for the foil thickness and leading edge shape. A comparison between the theory and published measurements suggests that the foil thickness exponentially attenuates the dipole sound pressure power spectrum by the product of the convection wavenumber and half the maximum section thickness. The ratio of the predicted dipole sound from the mean shear source to the source without mean shear is determined to be proportional to the ratio of the mean shear to the frequency of the sources.