  Fluid-structure interaction (FSI) problems are important because they may
induce serious damage to structures. In some FSI problems, the interaction
mechanism is strongly dependent on the wave propagation across the solid-fluid
interface. In this study, we attempted a quantitative evaluation of the effect
of the solid surface wettability on the wave propagation across the solid-fluid
interface with FSI in the case of longitudinal wave propagation vertically
towards the interface. During the experiments, while the water was continuously
compressed by the solid buffer motion, cavitation bubbles appeared being
originated from the buffer-water interface as a result of the transmitted
tensile wave propagating across the interface in a cycle. It was confirmed that
interfacial boundary condition as wettability could change the wave
transmission behavior owing to changes in the cavitation occurrence. It was
also confirmed that the worse the wettability, the severer the cavitation
intensity, and the greater the difference between the energy lost by the buffer
and the energy stored in the water. Consequently, the effect of the cavitation
inception on the wave propagation at the solid-fluid interface with FSI could
be quantitatively evaluated by considering the energy transferred from the
solid to the water.
