Vertical Motion Response of a Submerged Body Induced by Interfacial Solitary Waves

A simple time-domain numerical model is established to consider the interfacial solitary wave actions on submerged body and the body’s vertical motion. The vertical drag and inertial force on the moving submerged body induced by interfacial solitary wave is computed by Morison equation. The motion equation is solved by the fourth-order Runge-Kutta method. A horizontal submerged slender circular cylinder beneath the interface with forward speed is considered in this paper. The calculations show that when the depression internal solitary wave keeps close to the submerged body, the vertical forces on the body, including interfacial solitary wave force and buoyance, change greatly and the body moves downward with a great displacement in a short time. The main reason which results in the great vertical motion is the decrease of buoyance when submerged body moves into the less density water layer. It can be concluded that the great threat to submarine’s navigation is the density variation caused by interfacial solitary wave. The parameter effect of forward speed of the submerged body is also investigated.