A Multi-Fidelity Model for Wave Energy Converters

Abstract

The objective of this study is to develop a three-dimensional numerical model for a floating point absorber wave energy converter in the presence of sea waves, considering its interaction with a bi-fluid flow (comprising air and water). The primary aim is to create an efficient computational tool that achieves two key objectives: firstly, reducing the computational time typically associated with high-fidelity Computational Fluid Dynamics (CFD) models, and secondly, curing the lack of accuracy of low-fidelity asymptotic or projection-based reduced-order models in regions subjected to viscous and highly nonlinear effects. To address these objectives, we propose a multi-fidelity model based on domain decomposition. This approach combines a high-fidelity CFD solver, which accurately captures the behavior in viscous and nonlinear regions, with a Reduced Order Model (ROM) based on Proper Orthogonal Decomposition (POD), tailored for weakly nonlinear regions. By integrating these components spatially, we simulate the dynamics of the floating body within a unified framework. This methodology ensures precise predictions of the body's motion for both in-sample (reproduction) and out-of-sample (prediction) configurations.