Efficient flow reconstruction between dual tidal turbines: Large eddy simulation and reduced order modeling approach.

This article focuses on the computational analysis of flow dynamics between a pair of counter-rotating tidal turbines spaced approximately one rotor diameter apart, as part of the EU project NEMMO (The Next Evolution in Materials and Models for Ocean Energy). Using Large Eddy Simulation (LES) combined with the actuator line method (ALM) within the OpenFOAM framework, the study investigates how turbulence generated by the upstream turbine affects the downstream turbine's performance, leading to power imbalances. Proper orthogonal decomposition (POD) is applied to flow snapshots to develop reduced order models (ROM), revealing that fewer modes suffice to reconstruct flow between the turbines, while more modes are needed downstream due to increased turbulence and Kelvin–Helmholtz instabilities. These findings highlight the potential for computationally efficient modeling approaches to optimize turbine spacing and power management in tidal energy systems.