The Wiener-Hopf-Hilbert technique applied to problems in diffraction

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.A number of diffraction problems which have practical applications are examined using the Wiener-Hopf-Hilbert technique. Each problem is formulated as a matrix Wiener-Hopf equation, the solution of which requires the factor~sation of a matrix kernel. Since the determinant of the matrix kernel has poles in the cut plane, the Wiener-Hopf-Hilbert technique is modified to allow the usual arguments to follow through. In each case an explicit matrix factorisation is carried out and asymptotic expressions for the field scattered to infinity are obtained. The first problem solved is that of diffraction by a semi-infinite plane with different face impedances. The solution includes the case of an incident surface wave as well as an incident plane wave for an arbitrary angle of incidence. Graphs of the far-field are provided for various values of the half-plane impedance parameters. The second problem examined is diffraction by a half-plane in a moving fluid. This is solved without restriction on the impedance parameters of the half-plane and includes both the leading edge and trailing edge situations. The final problem is of radiation from an inductive wave-guide. Expressions are obtained for the field radiated at the waveguide mouth and the field reflected in the duct region.This work is funded by the UK Engineering and Physical Sciences Research Council (EPSRC