Local water slamming of curved rigid hulls

Abstract

We use the boundary element method (BEM) to study transient plane strain deformations of water induced by a rigid hull impacting at normal incidence initially stationary water occupying a half space with the goal of finding the hydrodynamic pressure acting on the hull. Water is assumed to be incompressible and inviscid, and its deformations to have zero vorticity. Thus deformations of water are governed by the Laplace equation. Challenging issues addressed are finding the free surface of water whose evolution is governed by a nonlinear partial differential equation, determining the a priori unknown wetted length, and ensuring that water maintains contact with the hull without penetrating into it. The solution of the problem using the commercial software, LSDYNA, resulted in water penetrating into a rigid hull. The developed BEM code has been verified by using the method of manufactured solutions. Computed results for the hydrostatic pressure on straight hulls and ship bow section are found to compare well with the corresponding experimental findings. It is found that the peak pressure acting near the terminus of the wetted length decreases with an increase in the radius of the circular hull.