Experimental Studies on Scale Effect of unstable Flow around the Stern

Abstract

To investigate the scale effect of an unstable phenomenon in self-propulsion tests experimentally, tests for an actual ship and the reduced scale ship models of 6 and 2. 5 meters in length are carried out.The results of the ship models tests showed an obvious unstable phenomenon.In the tests for an actual ship, fluctuation of flow field was observed also, but the major cause of it seems to be due to another disturbances from ship motions and so on.Thus it is concluded that in the flow around an actual ship, an unstable phenomenon does not occur or even if it happens, the effect of it on the flow is less than that of usual disturbances.