The movement of a rectangular cylinder in a liquid at short times after impact with formation of a cavity

Under consideration is some dynamical mixed problem concerning some separated impact and subsequent motion with constant velocity of a rectangular cylinder in an ideal incompressible heavy liquid. The specificity of this problem is that an attached cavity forms after impact and a new internal free boundary of the liquid appears. The shape of the cavity and the configuration of the outer free surface are unknown in advance and are to be determined during solution of the problem. Studying the problem is carried out at short times with consideration of the dynamics of the points of separation of the internal free boundary of the liquid. Location of the separation points at every time is defined from the Kutta–Zhukovsky condition. The influence is studied of the physical and geometric parameters of the problem on the shape of free boundaries of the liquid at short times. The asymptotic analysis is carried out of the internal free boundary of liquid near the separation points.