Numerical modeling of the freefall of two-dimensional wedge bodies into water surface

Abstract

In the current paper, two-dimensional freefall of wedge water entry is investigated in 1 degree of freedom. The defined problem is numerically studied using the STAR CCM+ software and by adopting an overset mesh approach. Three different chine wedges of 10°, 20°, and 30° deadrise angles are modeled. Kinematics of the considered wedges, impact loads, pressure, and the free-surface elevation around the considered wedges are presented. Based on the comparison of the computed vertical acceleration of the wedge of 20° deadrise angle against experimental data, it is determined that the proposed numerical method has relatively good accuracy in predicting the wedge response. The effects of deadrise angle and drop height on the kinematics of the wedges are also explored in different numerical simulations. Larger deadrise angle is found to yield lower and more transient vertical acceleration. It is demonstrated that impact force increases with an increase in depth, but finally approaches a constant value. Time histories of the pressure at three different points, located on the wedge wall, are also computed, indicating that an increase in the height leads to larger pressure at these points. However, when the mass is increased, the difference between the peak pressures at these points is strikingly reduced. Plots of the pressure distributions are also presented, which suggest that, as the submergence of the wedge increases, the pressure coefficient decreases. Furthermore, the pressure distributions indicate that, for the lighter wedge, the reduction in pressure coefficient is larger. Ultimately, the free surface elevation around a wedge during the freefall is presented. An increase in the pile-up is observed when the submergence height is increased, but for the wedge of 30° deadrise angle, the difference between free-surface profiles at specific times is far less than that of wedges of 10° and 20° deadrise angles.