Numerical study of slamming and whipping loads in moderate and large regular waves for different forward speeds

Abstract

This paper describes the development of a time-domain hydroelastic numerical model for investigating the slamming and whipping loads imposed on a ship traveling at different forward speeds. The numerical model integrates a beam model, the 3-D Rankine panel model, and the 2-D modified Logvinovich model. The tilt angle of the 2-D profile in the slamming model is determined by the direction of relative velocity, which takes the forward sailing speed into account. The computational results are validated against a segmented model test of a large cruise ship. The convergence of the model with different numbers of elastic modes and slamming profiles is studied to ensure that the numerical results are stable. The main contributor to the whipping response is found to be the vibration of the first-order elastic mode. The slamming force is sensitive to the longitudinal interval of the slamming profiles, especially in the stern. The characteristics of the slamming pressure under bow flare and the whipping response at midship are also investigated. The numerical and experimental whipping responses are found to be in good agreement, and the local slamming pressure based on the slamming profile is more accurate when considering the effect of the ship's forward speed.