Analysis of time harmonic wave propagation in an elastic layer under heavy fluid loading

This paper concerns assessment of the validity of elementary models of wave propagation in an isotropic elastic layer under heavy fluid loading as well as analysis of coupling effects due to uneven fluid loading. Dispersion curves, which describe propagation of dominantly flexural ‘in-phase’ waves and dominantly longitudinal ‘anti-phase’ waves in an elastic layer loaded by an acoustic medium at both sides, are compared with those obtained in the case of one-sided fluid loading. The latter are also compared with dispersion curves predicted by elementary theories of fluid-loaded plates. It is shown that the compressibility of the fluid dramatically extends the validity ranges of elementary theories and this phenomenon is explained.