Author(s)

P. C. Chu & C. Fan

Abstract

Waves form when the water surface is disturbed, for example, by wind or gravitational forces. During such disturbances energy and momentum are transferred to the water mass and sea-state is changed. For shallow water regions, the bottom topography affects the waves dramatically. Waves may cause an evident slant of the ocean surface with a large inclination angle of about 55o. When a high-speed rigid body strikes the wavy ocean surface, the random ocean slope largely affects its underwater trajectory. Identification of such an effect is a key point in the prediction of a fast moving rigid body in a water column. The probability density equation (PDF) of the ocean wave slopes was used to generate the stochastic surface slope. A 6-degree of freedom (DOF) model of a fast-moving rigid body is used with the stochastic sloping surface as its waterentry condition. The PDFs of the body location and orientation are obtained from results of 6-DOF model runs. From temporal change of these PDFs, the wave effect on the trajectory of a high-speed underwater rigid body has been identified. Keywords: body-flow interaction, 3D bomb trajectory prediction, 6-DOF model, STRIKE35, random waves, probability density function. 1 Introduction Movement of a fast-moving rigid body such as a bomb through a water column has been studied recently [1–3]. These studies have been motivated by a new concept of using a general purpose bomb such as the Mk-84 for mine/maritime improvised explosive device (IED) clearance in order to reduce the risk to

Keywords

body-flow interaction, 3D bomb trajectory prediction, 6-DOF model, STRIKE35, random waves, probability density function