A computational study on the performance and wake development of a tilted H-Shaped VAWT rotor

Wind energy is expected to play a key role in achieving challenging decarbonization objectives set by the current green energy transition. VAWTs are well-suited for the emerging market of floating offshore wind and hold significant potential to decrease the levelized cost of energy for offshore platforms. However, the flow field around a VAWT rotor is unsteady and three-dimensional due to the interaction between blades and vortical structures. Computational Fluid Dynamics is a crucial tool to study complex flow structures and optimize the machines at a reduced cost. This study presents a comprehensive 3D CFD investigation of the performance and wakes development trends of a straight-blade H-shaped VAWT operating in a tilted condition, a typical configuration for floating offshore installations. The VAWT model is studied at peak power and off-design TSR values. The predictions are analyzed by considering the complex flow field and near-wake development. The study finds that the 3D flow originating from the struts, the finite blade effects, and the tilted operating condition critically impact the machine's performance. The study provides an in-depth analysis of turbine aerodynamics and spanwise variations to investigate the fluid-dynamic phenomena and their implications on energy production.