Stefano Ubertini

University of Tuscia, Viterbo, Italy



Hull slamming refers to the impact between a ship hull and the water surface. Slamming impulsive loads are characterized by very a short time duration and may thus cause considerable vibration and local structural damages in the structure from stress concentration and fatigue. Free surface waves generated in the vicinity of the impacting hull also play an important role on the stress distribution, thus making their accurate prediction crucial in the structural design. This paper aims to numerically predict the free surface flow around an impacting hull along with the hydrodynamic loading on the hull using a free surface variant of the lattice Boltzmann method. The topology of the free surface is described by tracking the liquid mass fraction without the need of an additional transport equation, as in traditional CFD methods. The use of the lattice Boltzmann method also allows to model the movement of the hull within the grid, without the need of updating the mesh. This makes!

the method very efficient from a computational point of view. Numerical results are presented for simplified hull geometries and compared to analytical, numerical, and experimental data available in literature. The validation is performed on the hull deformation and hydrodynamic loading along with the free surface dynamics. Our results show that the present scheme is capable of closely simulating impulsive free surface flows with strong nonlinear behavior in the hull slamming problem, which is of great relevance to naval applications.