Diffraction near a bi-impedant half-plane

Calculations are presented for the diffraction of sound from a line source by an absorbing half-plane. The two faces of the half-plane have different impedance boundary conditions. Expressions are developed for a noise barrier whose surface is treated with two different acoustically absorbent materials. Results are given for the total far field for the leading edge (no wake present) and the trailing edge (wake present) situations. The calculations indicate that near the wake the field is strengthened, while being weakened elsewhere even when the source is not near the edge.