A Computational Fluid Dynamics Study on the Performance of Modified H-Shaped VAWTs for Tilted Operation Condition

Wind energy harvesting may see radical transformation with the introduction of new wind turbine concepts. The vertical axis configuration offers significant advantages that may promote the installation in deep waters, where only floating platforms are feasible and economically convenient. While experimental tests for multi-objective assessment are expensive, and analytical methods relying on blade element momentum are of limited fidelity, advanced, high-fidelity computational fluid dynamics (CFD) techniques are a promising tool for the performance prediction of wind turbines. CFD simulations enable critical evaluation of real-time, long-term aerodynamic loading and prediction across various operational scenarios. This paper presents a fully three-dimensional (3D) CFD investigation on the aerodynamics and near-wake development of a small-scale H-shaped vertical axis wind turbine (VAWT) and two modified versions suited to tilted conditions, typical for spar-buoy applications. An in-depth spanwise study of the three versions at the peak power condition is performed. The difference in the swept area and the coning angle effect in combination with the tilt condition are considered. The obtained results show significant, potential, contribution to the ongoing development of the floating-VAWT technology. The vortical structures development is also commented to provide better understanding of the physical phenomena taking place. Since the relevant energy harvesting capability being predicted for the newly designed turbines, further simulations aimed at demonstrating the engineering relevance of the machines, utility-scale models of the turbine. The numerical predictions confirm the high performance achievable by the HV-shaped wind turbines, providing valuable insights for its future installations.