Numerical study of the effect of flow control using plasma actuator on the aerodynamic performance of a VAWT

The increasing capacity of wind energy, alongside the growing demand for power, highlights the need for flow control methods to enhance the output of wind turbines, enabling the efficient utilization of wind energy resources. One active flow control method involves the use of plasma actuators, which inject momentum into the boundary layer to prevent flow separation, ultimately improving the aerodynamic performance of turbine blades. In this study, a numerical approach is employed to examine the effects of flow control using the SDBD (Surface Dielectric Barrier Discharge) plasma actuator model on the aerodynamic performance of a Darrieus vertical-axis wind turbine. The unsteady, pressure-based Navier-Stokes equations are solved in two dimensions using the finite volume method. One of the common challenges for vertical-axis wind turbines is dynamic stall and flow separation, along with their detrimental effects. Therefore, before applying plasma control, the flow physics around the Darrieus wind turbine is analyzed, with a focus on the aerodynamic forces and torques affecting the instantaneous torque generated by the blades. Subsequently, plasma actuators are positioned at three distinct chord wise locations on the airfoils, namely at 0.25, 0.5, and 0.75 chord lengths. The plasma dynamics are incorporated using user-defined functions (UDFs) according to the SDBD model. Results indicate that the 0.25 chord position is the optimal location for the plasma actuator among the tested positions, increasing the overall power coefficient of the turbine by up to 20%. Moreover, the plasma actuator effectively mitigates dynamic stall, eliminates vortex formation, and contributes to the enhancement of aerodynamic forces and torques. the primary effect of the plasma actuator is observed in the upstream flow region and during the blade’s downward motion, which leads to improvements in local blade torque and output power. The plasma actuator has little effect in the downstream region of the flow. Plasma actuators are most effective in the downward motion of the blade. However, they do not have a significant effect on the upward motion of the blade except at small angles. Therefore, the flow control actuator can be disabled in the upward phase to save more power consumption. It will eliminate the reverse Karman vortex formed in the downstroke of the blade, also will attenuate the counterclockwise vortex, which helps control stall and flow separation. the lift force will be improved in the downstroke and drag force will be reduced in overall.