Simulation of Ship Wakes in Water Tunnel Cavitation Testing of Models

Reliable cavitation testing of ship propulsors requires accurate modelling of the ship wake velocity field. This paper presents a progress report on efforts at the David Taylor Research Center (DTRC) to generate properly shaped velocity patterns in a water tunnel by means of partial length afterbody models. A survey of references is presented on the general topic of applications and techniques of wake simulation in water tunnels using a variety of means, including screens mounted normal to the tunnel stream; partial length (dummy model) hull representations; and full length geometrically scaled hull models. Three recent examples are described in some detail of successful wake-generating bodies designed for experiments conducted in the DTRC 36-inch Variable Pressure Water Tunnel. The wakes of these examples are taken in order of increasing degree of difficulty. In each case, there is a discussion of the target wake, the body design considerations, and the quality of the resultant simulated wake.