Numerical analysis of vertical axis wind turbine performance at varied angle-of-attack

A vertical axis wind turbine (VAWT) is the type of turbine that uses aerodynamic drag to rotate vertically and generate electrical energy. Wind energy is considered an important renewable energy source and the development of VAWTs is ever increasing. A household application of VAWT as a complementary energy source is considered. The study focused on the analysis of the performance of VAWTs at varied blade Angle-of-Attack (AoA). Two NACA Selig/Giguere series aerofoils were modelled for varied thicknesses and chord lengths to analyze the power of the turbine at different AoA using Computational Fluid Dynamics (CFD). A Dynamic mesh technique in the ANSYS Fluent 2019 R1 commercial software was used to model a three-H-shape VAWT that simulated a varied AoA as cam would on pivoting blades was effected through a User-Defined-Function. The varying AoA produce a higher momentum deficit in the wake, but also a faster wake recovery. The AoA reaches both the minima and maxima of the power it can produce before stalling wind over the aerofoil and forming large vortex shedding and wakes behind each blade that should have been less from a low-speed VAWT. Consequently increasing noise levels which is undesirable for urban applications. The varied AoA show a bimodal distribution of vortex shedding retracting from the blades.