Analytical study of excitation and measurement of fluid-solid interface waves

Analytical analyses are performed to investigate the pressure and particle velocity responses in fluid/solid half spaces subject to impulsive sources. This study has significance for underwater seabed characterization efforts that use interface waves. Results show that pressure (e.g., measured by hydrophones) in the fluid is more sensitive for interface wave sensing than particle velocity (e.g., measured by geophones) at the fluid-solid interface. Both types of impulsive point wave sources, explosive action in fluid and mechanical action on solid, are investigated with regard to the excitability of interface waves. Analyses show that a mechanical load applied normal to the interface generates higher amplitude interface waves, relative to the acoustic wave amplitude, than an explosive load in the fluid. The effect of explosive source height is also investigated. Results show that Scholte wave amplitude is affected by the explosive source height, and decays quickly with increasing height. However, explosive source height has little effect on generated leaky Rayeligh wave amplitude.