Diffraction of sound by a rigid screen with a soft or perfectly absorbing edge

Abstract

A solution is obtained for the problem of the diffraction of a plane wave sound source by a semi-infinite plane. A finite region in the vicinity of the edge has a soft (pressure release) boundary condition; the remaining part of the semi-infinite plane is rigid.

This solution is then used to derive an approximation for the behaviour of a rigid barrier with an absorbing edge. It is concluded ,that the absorbing material that comprises the edge need only be of the order of a wavelength long to have approximately the same effect, on the sound attenuation in the shadow side of the barrier, as a completely absorbent barrier.