Reduced order model of offshore wind turbine wake by proper orthogonal decomposition

•High-Fidelity (HF) simulation combining Finite Volume (FV) strategy with Proper Orthogonal Decomposition (POD) and Galerkin projection at high Reynolds number.•Full-order simulations on NREL 5MW offshore wind turbine conducted through Sliding Mesh Interface (SMI) technique.•In depth evaluation of coherent structure formation and energy enrichment in modes through model reduction technique.•Detailed quantitative and qualitative comparison of wake evolution from Reduced-Order Model (ROM) and High Fidelity (HF) simulations. A wide range of previously designed methods for faster parametrization of partial differential equations requires them to be solved using existing finite volume, finite element, and finite difference solvers. Due to the requirement of high degrees of freedom to accurately model the physical system, computational costs often becomes a bottle-neck. It poses challenges to conducting efficient repeated parametric sampling of the input parameter that disrupts the whole design process. Model reduction techniques adopted to high fidelity systems provide a basis to accurately represent a physical system with a lower degree of freedom. The present work focuses on one such method for high-fidelity simulations that combines finite volume strategy with proper orthogonal decomposition and Galerkin projection to test reduced-order models for high Reynolds number flow applications. The model is first benchmarked against flow around a cylinder for which extensive numerical and experimental data is available in the literature. The models are then tested to full-scale NREL 5MW offshore wind turbines to evaluate wake evolution in the downstream direction. The simulations results show relative errors of wind turbines for the first seventy modes approach 4.7% in L2-norm for velocities.