Experimental Analysis of Cavitaion E ects on Drag Force and Back Pressure of Circular Cylinder with Free Turbulence

Abstract

Abstract. The characteristics of a cavitation water tunnel test setup and the experiments of cavitation around a circular cylinder with free stream turbulence are presented in this paper. The Reynolds number of ow is limited in the range of 1:26 105 to 3 105 and the far upstream ow has free turbulence. Drag force, back pressure, location of cavitation inception, length of cavity and appearance of cavitation are measured or observed and their results are presented here. It was found that the cavitation e ects on the boundary layer and separation of ow over the cylinder and drag force become minimum at the cavitation number of 1.94. The cavitation inception occurs in the sub-layer and at an angle of about 105 , with respect to ow direction (inception location depends on Reynolds number). The back pressure coe cient becomes maximum at the cavitation number of 1.94.