This paper presents a coupled Computational Fluid Dynamics and Fluid Structure Interaction model of the Bombora wave energy converter. The model consists of three components – the membrane, the power take off system (PTO), and the ocean – which are solved together to capture the device behaviour. The ocean (and waves) are solved using the volume-of-fluid method, the membrane is solved using a simplified Finite Element (FE) model, and the PTO is solved using a thermodynamic model of the ducting and turbine. OpenFOAM is used for the VoF models, extended by the waves2Foam toolbox. The membrane and PTO models are implemented from scratch as separate custom libraries, using OpenFOAM’s base classes.
Comparison between the fully coupled inflation model and the uncoupled inflation model indicates that, as expected, the dynamic effects of the water cannot be ignored. It is expected that a combination of increased damping, and additional membrane mass may be able to account for a large part of the fluid loading. As a consequence of the different response times for each component of the model simulation run-times are excessive, and these simulations seek to quantify the certainty of some of the assumptions in the simplified models. However, future work will investigate alternative methods for coupling these models together.