Aerodynamic Sound due to a Point Source near a Half-plane

Abstract

In this paper we extend Jones's analysis of the diffraction of sound in three dimensions by a semi-infinite plane with a plane vortex sheet attached in the two cases when the wave equation is in the form for still air and when convection is present. It is found that in so far as the moving medium is concerned the imposition or otherwise of the Kutta-Joukowski condition does not have much influence on the scattered field away from the diffracting plane; when the source is near the edge the field has the same directionality and order of magnitude. On the other hand, near the wake the Kutta-Joukowski condition produces a much stronger field than elsewhere even when the source is not near the edge. We also conclude that the same phenomenon occurs for arbitrary sources and not just for the line source discussed by Jones.