Simulation on flow control strategy of synthetic jet in an vertical axis wind turbine

Abstract

The purpose of present paper is to adopt two-dimensional numerical simulation to investigate the flow field and flow control effect around a straight-bladed vertical axis wind turbine (SB-VAWT) with utilizing synthetic jet active flow control technique which has become a research focus. The numerical simulation results for power coefficients of clean SB-VAWT have been validated by comparing with experimental results. In order to take account of the control effect of orifice quantity, jet momentum coefficient and synthetic jet control strategy, the numerical simulation of the SB-VAWTs with different number of orifices and 5 different control strategy of synthetic jet actuator have been carried out by using unsteady Reynolds-averaged Navier–Stokes (URANS) in ANSYS FLUENT with Realizable k–ε turbulence model and Scalable wall function. The aerodynamic coefficients (power coefficient, torque coefficient) and vorticity field around the blades of the SB-VAWT are comprehensively obtained. The results show that the synthetic jet actuator has positive effect to improve the aerodynamic performance for SB-VAWT. The utilization of synthetic jet actuator with 2 orifices around trailing edge of blades and upward parabola synthetic jet control strategy at 0.035 jet momentum coefficient increases the power coefficient by 15.2%. Besides, this increment in power coefficient decreases with the increasing number of orifices and the synthetic jet actuator brings about more intense load fluctuation than the clean one. Furthermore, the trailing vortices produced and blades less interact with each other, resulting in less vorticity magnitude of shedding vortices and less complexity of flow structure.