عنوان مقاله [English]
Darrieus type vertical axis wind turbine is an appropriate choice for local electricity generation in urban environments. The major aerodynamical challenge in these turbines is dynamic stall which drastically affects the aerodynamic performance of the turbine. In this study, the effect of plasma actuator on aerodynamic performance of a Darrieus type vertical axis wind turbine was numerically investigated. Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations were employed, accompanied with k-ω SST turbulence model. Suzen-Hoang model was used to model plasma actuator that calculates body force source term representing plasma actuator effects. The pressure-based finite volume method was utilized to solve the governing equations. First, the physics of dynamic stall in turbine blade was explored. Results show that the contribution of connection point moment in instantaneous moment of a blade is more than 25 percent. Moreover, counter clock-wise vortex in the suction side of blade was found to have a significant role in the blade's performance. To study plasma actuator effects, three test cases of inboard, outboard, and two side actuation, were considered and compared with the clean blade (no plasma actuator). The inboard plasma actuator weakened the dynamic stall vortex, increased lift, and decrease drag force in the down-stroke motion of the blade. Nevertheless, plasma has no effect during the up-stroke motion since the flow is attached to the blade's surface. The inboard actuation is effective for blade azimuth angles in the range of 70 to 180 degrees, and the outboard actuation is effective in blade azimuth angles between 180 to 290 degrees. In conclusion, plasma actuator leads to a 10 percent enhancement in power production for inboard actuation and two-sided actuation, but no significant effects were observed for outboard actuation.