On the Transfiguration of Water Waves Propagating into a Uniform Wake

Abstract

In order to investigate the interference between surface waves and a frictional wake of a ship, a simple mathematical model, such as a current of uniform width and uniform velocity in the surrounding still water upon which a regular train of waves propagates, is considered. The analysis is based on the assumption that the fluid is inviscid and the motion is irrotational except on the boundary of the wake or current. The result of calculation shows a remarkable change of the incident wave when it propagates accross the boundary of the wake. When the direction of the incident wave is parallel to the wake belt, a considerable attenuation of the wave height is resulted. An experiment in a circulating water channel is conducted to observe the transfiguration of waves inside the wake, and a qualitative agreement with the theoretical result is obtained.