### ASA 127th Meeting M.I.T. 1994 June 6-10

## 1aSA10. Diffraction of short wavelengths by a circular elastic plate in a
contrasting baffle.

**Gerry R. Wickham
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*Dept. of Math., Univ. of Manchester, Manchester M13 9PL, England, UK
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The scattering of sound of wavelength 2(pi)/k by a circular elastic plate
of radius a in an infinite planar contrasting baffle is exactly formulated in
terms of a singular integral equation of the second kind using a novel
extension of the Wiener--Hopf technique. The exact solution of this equation is
easily derived analytically as a rigorous convergent expansion that is also
asymptotic in the limit ka->(infinity). Thus it is possible to derive explicit
asymptotic formulas for the scattered field in terms of the factorization of
the standard Wiener--Hopf kernel corresponding to the canonical diffraction
problem for two adjoining semi-infinite compliant surfaces. The special cases
of an elastic plate in a rigid baffle and a rigid plate in an elastic baffle
are considered in detail. It turns out that the asymptotic forms for the
diffracted far fields may be simplified dramatically using a factorization
procedure devised by the author and Andrew Norris and that these results are
uniform in the fluid loading parameter.