In:
The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 70, No. S1 ( 1981-11-01), p. S80-S80
Abstract:
A rigorous theory based on the extended boundary condition method is proposed to solve the problem of diffraction from a fluid/solid interface which has periodic roughness. The extended boundary condition is derived by applying Green's theorem to the total fields and the Green's functions for the periodic surface in the fluid region and the solid region separately. A complete set of basis functions (Fourier series) is then chosen for the expansions of the unknown displacements and the tractions on the surface. The set of integral equations is reduced to simple matrix equations which are solved for the coefficients of the basis functions of the surface fields. The diffraction efficiencies of the incident plane wave from the fluid to the reflected compressional waves and the transmitted compressional and shear waves of different Floquet modes are calculated. Energy conservation is used to check the accuracy of the numerical results. The case of a lossy (viscoelastic) solid is included in the study. For experimental verification, an acrylic block was machined to have a symmetric sawtooth surface profile with a height 0.49 mm and a period 5.08 mm. The scattering from this block immersed in water is measured at 500 kHz. The diffraction efficiencies of different Floquet modes in the water are measured versus angle of incidence. Very good agreement is achieved between the theory and the experiment.
Type of Medium:
Online Resource
ISSN:
0001-4966
,
1520-8524
Language:
English
Publisher:
Acoustical Society of America (ASA)
Publication Date:
1981
detail.hit.zdb_id:
1461063-2
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