Numerical Simulation of Wave Slamming on a Flap Type Oscillating Wave Energy Device.

This paper presents the numerical investigations of an oscillating flap-type wave surge converter device operating in extreme sea states. We use the open-source CFD library OpcnFOAM to carry out the two-dimensional numerical simulations. A preliminary study is done to verity the convergence of our results while scalability tests confirm the high-performance computing capabilities of OpcnFOAM and the possibility to extend this study to large three-dimensional configurations. The Oyster flap-type device is simulated with both incompressible and compressible solvers and results arc compared against previous numerical and experimental results. It is shown that an incompressible solver can capture well the dynamics and general behavior of the flap device. Nevertheless, the slamming events captured in the laboratory can only be reproduced with the aid of a compressible solver, which takes into account density changes in the air and water phases. The numerically captured slamming events only take place if there is a preliminary formation of trapped air pockets on the seaward side of the flap. The entrapped air is subject to further compression and expansion thus confirming the importance of compressibility and aeration effects in agreement with thoughts based on past experiments and numerical simulations. [ABSTRACT FROM AUTHOR]