Darrieus type vertical axis wind turbines have several advantages over other wind turbines for local electricity generation in urban environments. However, the main aerodynamic challenge is the negative impacts of the dynamic stall phenomenon on the turbine performance. This study numerically scrutinizes the effects of plasma actuators on the dynamic stall control and performance improvement of a Darrieus turbine. For this sake, unsteady Reynolds-averaged Navier–Stokes equations are solved using a pressure-based finite volume method. The Suzen–Hoang plasma actuator model is employed to calculate the body forces attributed to the plasma actuator. First, the dynamic stall characteristics of the turbine blade with no plasma actuator are explored. Then, three plasma actuator configurations (i.e., inboard, outboard, and double-sided) are considered. According to the results of the clean blade, the aerodynamic performance mainly depends on the reverse Karman vortex formation at the onset of the down-stroke motion and counterclockwise vortex formation on the blade suction side. The results of plasma configurations indicate that the inboard and double-sided actuators enhance the turbine power output by 10%, while the outboard actuator effects are negligible. Moreover, the plasma actuator is effective only in the down-stroke motion of the blade. Results also show that the inboard and double-sided plasma actuators eliminate the reverse Karman vortex and significantly reduce the counterclockwise vortex size, increasing the lift force and connection point moment. Consequently, the inboard and double-sided plasma actuators remove the negative torque generation in azimuth angles of 135° to 180°, primarily responsible for the output power enhancement.

Abstract. Inlet performance has an important role in the operation of air-breathing propulsion systems. In this study, performance of a supersonic axisymmetric mixedcompression inlet in the supercritical operating condition is numerically studied. The e ects of free-stream Mach number and engine-face pressure on performance parameters, including mass ow ratio, drag coe cient, total pressure recovery, and ow distortion, are investigated. For this sake, a multi-block density-based nite volume CFD code is developed, and Reynolds-averaged Navier-Stokes equations with Spalart-Allmaras oneequation turbulence model are employed. The code is validated by comparing numerical results against other computational results and experimental data for two test cases of inviscid ow in a two-dimensional mixed-compression inlet and ow in an external compression inlet. Finally, the code is utilized for the investigation of a speci c supersonic mixed-compression inlet with the design Mach number of 2.0 and length-to-diameter ratio of 3.4. Results revealed that the increment of free-stream Mach number leads to the decrease in total pressure recovery and drag coe cient, while mass ow ratio and ow distortion increase. The e ects of engine-face pressure on performance parameters showed that by increasing the engine-face pressure, mass ow ratio and drag coe cient remain constant, while total pressure recovery increases and ow distortion decreases.