URANS prediction of the slamming coefficients for perforated plates during water entry

The slamming coefficients for perforated plates of various perforation ratios and layout configurations were predicted using Unsteady Reynolds-Averaged Navier-Stokes (URANS) solver STAR-CCM+. The numerical model was validated by comparing with experimental measurements of slamming coefficient for a circular cylinder. The slamming coefficients and free surface profiles of perforated plates were then predicted at full-scale. It was found the air compressibility plays an important role by studying flat plate water entry phenomena. For perforated plates with small gap length/width ratios, the ability of the trapped air to evacuate through the space between the bottom of the plate and free surface is similar. For perforated plates with different gap number at a fixed perforation ratio, the slamming coefficient is increased with the increase in gap length/width ratio. However, a further increase in length/width ratio may impose a negative impact on the escape of trapped air due to the increase of gap number.