Spherical wave scattering by a rigid screen with a soft edge

An analytic solution for the diffraction by a half-plane is given for a spherical wave incidence in still air as well as in a moving fluid. This is important because point source is known as a fundamental radiating device. The half-plane is rigid except for a soft strip in the vicinity of the edge. The diffraction coefficient in both cases is strongly dependent upon frequency. The calculations indicate that the field is enhanced as a result of fluid motion and this enhancement of the field is independent of the direction of flow. It is found that the magnitude of the far field on the source side of the semi- infinite plane seems to depend more critically on the length of the soft strip and the wave number.