The motion of a rigid body impelled by sea-wave impact

A wave breaking against a sea wall causes high pressure gradients to act along the sea bed, pushing objects away from the wall. This situation is modelled using pressure impulse theory to show that, for a large object near a sea wall, the impulsive force due to the wave will move the object. This force can be found, given knowledge of the added mass and volume of an object. In particular, if the wall is thought of as a plane, gently sloping beach, then this theory may explain how shingle beaches are graded according to the size of the shingle, with larger boulders being moved farthest by the impact of a wave. In order to obtain estimates for the distances moved up, or down, the beach, a single boulder is treated as a spherical body which is free to move.