Experimental Analysis of Cavitaion Effects on Drag Force and Back Pressure of Circular Cylinder with Free Turbulence.

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 flow is limited in the range of 1:26*10^5 to 3*10^5 and the far upstream flow 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 effects on the boundary layer and separation of flow 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 flow direction (inception location depends on reynolds number). the back pressure coefficient becomes maximum at the cavitation number of 1.94.