Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : November 02, 2019 - November 04, 2019
Fluid-structure interaction (FSI) is important in the design of plants and piping systems. In the previous studies, it has been observed that cavitation bubbles were incepted at the solid-fluid interface with FSI. It has confirmed that the transmission behavior of the stress/pressure wave across the solid-fluid interface was changed due to the cavitation inception. However, quantitative evaluation of the effect of cavitation generation on wave propagation at a solid-fluid interface with FSI was not sufficient. This study aims to quantitatively evaluate the effect of dynamic cavitation inception on wave propagation at a solid-fluid interface with FSI by considering energy transfer from solid to fluid. An impact experiment was conducted with a free-falling projectile which hit the cylindrical solid buffer placed on top of the water surface within the elastic tube. The surface wettability of the buffer and the surface tension of water were varied to change the intensity of cavitation. It was confirmed that at the interface with worse wettability (large contact angle), energy transmitted into water was consumed by cavitation inception from the solid-fluid interface, thus the potential energy of water in the pipe was reduced. Then, the kinetic energy reduction of the buffer and the potential energy of water in the tube were estimated theoretically. The potential energy of the in-pipe water was 66%, 71% and 72% of the lost kinetic energy of the buffer with contact angles of 93.2°, 77.1°, and 12.5°, respectively. Consequently, the effect of cavitation inception at the solid-fluid interface with FSI on wave propagation could be quantitatively evaluated by considering the energy transferred from the solid to the water in the pipe.
