Numerical Simulation of Heavy Water Shipping

Rough-sea conditions can result in shipping of water on the deck of vessels. In particular, our ongoing investigation is focused on the bow-deck wetness in head-sea conditions for a moored ship, i.e. without forward speed. Though in practice three-dimensional effects matter, two-dimensional investigations are undertaken to gain basic insights, before developing more realistic three-dimensional approaches. In previous Workshops, a combined numerical-experimental analysis has been presented. In particular, a potential flow model has been assumed and a Mixed Eulerian-Lagrangian method has been adopted to solve the unsteady interaction between the body and the free surface. The Boundary Element Method (BEM) has been used as numerical solver. In the experiments, a two-dimensional nearly-rectangular ship model has been placed in a narrow wave flume, and the first water-on-deck event due to incoming waves generated by a flap wavemaker has been investigated. The model is fixed and resembles the centerplane of a ship. Comparisons confirmed the validity of the adopted flow model and the efficiency of the BEM in capturing the water shipping from a global point of view as well as in predicting some local features, such as the initial pressure along a superstructure under the impact of the shipped water.