Scattering by quasi-symmetric pipes

A hypersingular boundary integral method for the prediction of radiation from a straight circular pipe with arbitrary end profile has been developed. The technique represents an extension of established procedures for axisymmetric pipes with the addition of recent advances in special function and quadrature theory to simplify the implementation. The resulting code is applied to two sample problems: first, the prediction of radiation of a plane wave mode from a pipe with its ends cut by an inclined plane, representing the `scarfed intake' proposed for reduction of aircraft engine noise. Second, the method is used to examine scattering of an incident azimuthal mode by a multi-lobed profile, characteristic of the `chevron' nozzles proposed for jet engine exhausts.