Coupled phase field-immersed boundary method for simulating wave energy converters

A bottom-hinged Oscillating Wave Surge Converter (OWSC) can be best described as a flat plate that oscillates due to the hydrodynamic forces applied to it by the action of ocean waves. To simulate this device, a phase field method is implemented in an existing multi-block generalized coordinate finite volume solver, GenIDLEST, which uses a collocated grid arrangement within the framework of the fractional-step method. The phase field method is chosen for its relative ease of implementation and proven boundedness and conservativeness properties. The method falls under the category of diffuse interface methods which convect as well as smooth the freely evolving interface between air and water. Extensive validation and verification using standard test cases, such as droplet in shear flow, Rayleigh Taylor instability, and the Dam Break Problem are carried out. This development is then coupled with an existing Immersed Boundary Module which is used to simulate the presence of moving bodies and again verified against test cases, such as the Dam Break problem with a vertical obstacle and heave decay of a partially submerged buoyant cylinder. Finally, a relaxation zone technique is used to generate waves and a numerical beach technique is used to absorb them. All these techniques are then combined to simulate the Oscillating Surge Wave Converter.