Comparative analysis of counter rotating and conventional vertical axis wind turbine

Implementing small and medium sized vertical axis wind turbines (VAWT) in rural and urban regions is of focus for many countries including India. Counter rotating vertical axis wind turbine is relatively simple in design and has better aerodynamic performance compared to conventional VAWT. This paper computationally investigates the performance of counter rotating and conventional H-type vertical axis wind turbine. Comparative analysis at various tip speed ratios (TSR) indicates, that at optimum TSR, the power output of the counter rotating wind turbine is about 25% greater than H-type VAWT of same size. This enhancement can be attributed to the reduction in tip vortex shedding and energization of downstream flow.