Pages 103-120
The scale effect on the wake distribution of a full form ship model is studied experimentally and theoretically on a geosim series of a tanker (the lengths are 12m, 7m, 4.7m and 3.5m). Wake as well as boundary layer velocity distributions are measured by 5 hole Pitot tubes at several stations for each model in towing tanks. The result of measurements is compared with the theoretical results by three existing methods for predicting scale effects of the wake and boundary layer. The most important results obtained are 1) the width of the wake becomes narrower as the dimensions of the model increase, 2) the value of the wake fraction becomes smaller in the wake-peak regions, such as in the neighborhood of the center plane of the model and in the plateau-like zone, as the dimensions of the model increase, and 3) thus, the prediction methods which consider the scale effect in velocity defect as well as in wake width are superior to the one which does not consider the scale effect in velocity defect.
