Sound directivity pattern radiated from small airfoils.

Verification of Curle's (1955) point dipole sound theory as a means for predicting the level and directivity of sound radiated from rigid surfaces in flow. A presented comparison between theory and experiment is shown to provide evidence that airfoils in flow, whose dimensions are small in relation to the wavelength of the radiated sound, radiate like point dipoles in apparent support of Curle's theory.