A CFD Study on the Performance of Modified H-Shaped VAWTs for Tilted Operation Condition

Wind energy harvesting may see a radical transformation with the introduction of new wind turbine concepts. In fact, the vertical axis configuration offers significant advantages that may accelerate extending the installation capabilities to deep waters, where only floating platforms are feasible and economically convenient. While experimental tests for multi-objective assessment are expensive in terms of costs and time, and analytical methods relying on Blade Element Momentum (BEM) are of limited fidelity, especially when considering novel rotor configurations, advanced simulations carried out using high-fidelity Computational Fluid Dynamics (CFD) techniques are a promising tool for evaluating the aerodynamic performance of wind turbines. CFD simulations enable critical evaluation of real-time, long-term aerodynamic loading and prediction across various operational scenarios. This technique can thus be crucial for optimizing the efficiency of wind turbines and reducing the LCOE. This paper presents a fully 3D CFD investigation on the aerodynamics and near-wake development of a small-scale H-shaped VAWT and two modified versions, adapted for operating in tilted conditions, which is 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 have shown the potential to contribute to the ongoing development and advancement 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, and provide valuable insights for its future installations.