A numerical simulation of shear forces and torques exerted by large-amplitude internal solitary waves on a rigid pile in South China Sea

Large-amplitude internal solitary waves (ISWs) contain enormous energy, and induce strong convergence and divergence of horizontal velocity in the propagation, which may cause strong destructive power to ocean engineering structures. In this paper, the wave field of ISWs is obtained using the generalized KdV model (GKdV model for short) for continuous stratified ocean in the South China Sea, furthermore the shear forces and torques exerted by ISWs on a supposed rigid pile are calculated. It is found that, the shear force is largest at the turning point of the horizontal velocity induced by ISWs, and the torque is largest at the pile foot. In the course of a soliton (about 10 min), the directions of the shear forces and torques alter twice and the values thereupon change greatly. These results are of benefit to revealing the mechanism of destructive power exerted by large-amplitude ISWs on a pile.

► The continuous vertical distribution of horizontal velocity of ISWs is obtained.
► The shear force and torque exerted by ISWs on a rigid pile are calculated.
► The shear force is largest at the turning point of horizontal velocity of ISWs.
► The torque is largeat at the pile foot.