Numerical Analysis of the Overlap Effect Between Blades at Four-Bladed Rooftop VAWT

This work presents a numerical analysis of a four-bladed Rooftop vertical axis wind turbine (VAWT). The effects generated on the performance of turbine by the overlap variation between blades of wind rotor were analyzed. The numerical simulations were developed using commercial software based on Computational Fluid Dynamic (CFD). Each one of the models generated was built in a 3D computational model. A sliding mesh model (SMM) capability was used to present in dimensionless form the moment coefficient and power coefficient of the wind turbine based on the relationship between wind speed and rotor rotational speed. The results show that the aerodynamic performance is better with overlap between rotor blades, resulting in a significant increase in the moment coefficient and power coefficient. Having that in the cases of four-bladed Rooftop rotor with overlap both coefficients increase about 29% comparing with four-bladed Rooftop rotor without overlap between blades.