2D model of a floating body under nonlinear waves

A model describing the dynamics of a floating body by solving the NS-equations in a moving grid framework with free surface is presented. The model has several interesting features, like the peculiar way of describing: a) the grid movements; b) the slip boundary conditions in presence of a wet and dry interface; c) the generation of waves and, to some extents, the sponge layers. The investigated feature is the ratio between the oscillation of the floating body and the wave oscillation, which is usually quite overestimated by viscousless models when the load frequency is close to the floating body eigenfrequency. A simulation of this condition with the non-linear model reproduced much more closely the experimental results described in Ruol and Martinelli (Comsol User Conference, 2007) than the corresponding simulation carried out with a classical model based on linear waves and irrotational flow.