Dynamic Stall Control for a Vertical-Axis Wind Turbine Using Plasma Actuators

Abstract

Dynamic stall is a major challenge for vertical-axis wind turbines (VAWTs) as it negatively impacts the aerodynamic performance of VAWTs, resulting in a reduction in net power output from the turbines. This study explores the use of alternating current dielectric barrier discharge plasma actuators for controlling dynamic stall on a VAWT. The flow control process is resolved using a two-dimensional unsteady Reynolds-averaged Navier–Stokes equations simulation with a Reynolds stress turbulence model adopted. The macro-effect of the plasma discharge on mean flow is modeled by an empirical body force model. The detailed flow actuation procedure is simulated. Numerical results show that the flow control process is dominated by the spanwise vortices, which result from the interaction between the plasma discharge and separated flow. The spanwise vortices not only prevent the development of a leading-edge separation bubble into a dynamic stall vortex, but also suppress the flow separation at the trailing edge. The application of plasma forcing has been found to greatly enhance the aerodynamic performance of the turbine in terms of the moment coefficient and averaged power coefficient of the turbine blades. Furthermore, we examine how the positioning of the plasma actuators and the freestream wind velocity affect flow control. The optimal actuation location is determined, and the plasma actuators are seen to be able to substantially enhance the net power output of the blades at all freestream speeds.