Diffraction by a thick half-plane with an absorbent end face

This paper considers the two-dimensional acoustic problem of the diffractio n of a plane wave by a thick half-plane of width 2b with rigid sides and an absorbent end face. The solution method is to superpose known solutions fo r a duct constructed from two rigid semi-infinite parallel planes a distanc e 2b apart; the known solutions used are the diffraction of a plane wave by the duct and the radiation of an arbitrary mode from within the duct. The work has application in the design of noise barriers and results are presen ted to illustrate the effectiveness of the absorbent end in noise reduction .