Experimental investigation on the multiphase flow characteristics of oblique water entry of semi-closed cylinder

Abstract The multiphase flow characteristics of the oblique water entry of semi-closed cylinders is investigated experimentally. The results from the experiment are used to analyze the flow mechanism and to validate the numerical simulations. In the experimental setup, a high-speed photography technique is used to capture the process of water entry based on digital video images. It can be observed that the cavity is formed in three (3) flow modes namely the fluctuation cavity, the transition cavity, and the blurry rippling cavity. The transparency of the cavity surface decreases, while the fragmentary and blurry rippling increases, with an increasing inclined angle of the cylinder. Owing to the instability of internal flow structure and the degree of cavity closure, the cavities of three (3) flow modes occur in sequential order from clear fluctuant cavity, rippling fluctuant cavity, to continuous blurry and fragmentary ripples. The cavity evolution is also found to affect the structure of multiphase flow field and the dynamic characteristics of semi-closed cylinder.