Assessment of an advanced finite element tool for the simulation of fully-nonlinear gravity water waves

A rigorous analysis of the water wave modeling capabilities of the advanced multipurpose CFD code Fluidity is presented. The study focused on the simulation of gravity water waves; their detailed understanding being fundamental to the design of many offshore (marine) solutions, including the emerging fields of wave energy conversion and floating offshore wind applications. Both small amplitude (linear hydrodynamics) and finite amplitude (nonlinear hydrodynamics) regular waves were simulated in a two-dimensional Numerical Wave Tank. To study the nonlinear wave, two wave generation techniques were adopted, and comparisons with a high-order potential flow theory were made. The wave group and the wave phase velocities showed excellent agreement with analytical solutions. The generation of nonlinear water waves was implemented using two different methodologies, i.e., a depth-constant piston-mode velocity distribution and a fifth-order Stokes velocity distribution. In both cases, a qualitative analysis indicated very good agreement with the expected fluid behavior. This is an abstract of a paper presented at the Proceedings of the Twenty-Second International Offshore and Polar Engineering Conference (Rhodes, Greece 6/17-22/2012).