A note on the diffraction by a semi-Infinite thick half plane, and a semi-infinite cylindrical rod with an absorbent end face

Abstract

The known solutions for: (i) A plane wave incident on two rigid semi-infinite parallel plane distance 2b apart, (ii) The radiation of an arbitrary mode from two parallel rigid semi-infinite plates 2b apart, are used to construct the solution of the problem of the diffraction of a plane wave by a semi-infinite thick half plane (thickness 2b), whose sides are rigid and whose end face is absorbent. The method used is simple superposition of the solutions (i) and (ii). The problem solved has applications in noise barrier design. Analogously by using the known solutions for the diffraction of a plane wave by, and the radiation of an arbitrary mode from, a rigid hollow cylindrical semi-infinite duct, the solution for the diffraction of a plane wave by a thick semi-infinite rigid rod with an absorbent end face can be obtained.