Fluid resonance in the narrow gap for a ship close to the vertical caisson on impermeable and permeable beds

Abstract

The behavior of fluid resonance in the narrow gap between a ship and a vertical caisson on impermeable and permeable beds is investigated. A two-dimensional viscous numerical flume with the permeable module is established, where the influence of impermeable and permeable beds on resonant behavior is focused. Numerical studies show that the existence of foundation bed decreases the resonant amplitude in the gap; while the resonant amplitude further decreases when considering the permeable effect of bed. This is mainly due to the fluid that can flow out of the box-wall system through the permeable bed. The increased influence of impermeable and permeable beds can be observed with the increase of box draft and gap breadth. Larger bed thicknesses and smaller incident wave amplitudes can also lead to more significant foundation bed effects. Finally, the influence of permeable foundation bed can also decrease the wave amplitude at the low-frequency range.