Many scholars have since investigated the aerodynamics, actuation frequency, and the monument range of the SJAs. The synthetic jet actuator (SJA) is still the new technology for wind turbines blades, which needs to be studied. The actuation frequency was optimized in the above study. Both numerical simulation and wind tunnel experimental result show that unsteady blowing is one of the most advanced solutions for flow separation. Pulsed blowing was adopted for the separation control by Coiro et al. used steady blowing and suction for separation and circulation control on an elliptical airfoil, which indicated that blowing is more effective than suction. Mitsudharmadi and Cui implemented the coflow jet concept on low Reynolds number airfoil and the results show that the momentum coefficient is found to be in the range of 5% and 13% when CFJ concept was used effectively. The blowing and suction control method was studied in detail. Dygert and Dang studied the same experimental rig and the same conclusion was obtained. Kummer and Dang embedded a crossflow fan near trailing edge into a thick wing for raising lift and the results show that the stall AOA is delayed to 40 degrees and the lift coefficient is enhanced to 6. In recent years, the experimental and numerical research about wind turbine aerodynamics covers a wide variety of aspects including the control method and the dynamic wall. The aim of flow control is to reduce the separation zone and flow resistance. The energy decreases, the lift of airfoil is reduced, and the resistance grows by the separation. There is a great demand for investigating and exploiting a simple and useful control approach to suppress the flow separation on the blade surface and enhance the aerodynamic performance of blade.įlow control method is an important research field of fluid mechanics, which has been pushed more than 50 years ago. The flow separation phenomena will appear on the suction surface of wind turbine blade at the high angles of attack (AOAs), which affects the aerodynamic performance of wind turbine blade seriously. Wind turbine blade always works at high angle of attack even at deep stall condition.
The research on wind turbine blade’s aerodynamic characteristics and performance has been an important subject of wind power technique. The aerodynamic characteristics of wind turbine blade are directly related to the wind turbine generator’s efficiency. Wind turbine is one of the mechanisms used to accomplish the transformation of wind energy into electric energy and it is the key part of wind turbine generator. However, the lift coefficient increases and drag coefficient decreases when AOA is 15 degrees and 20 degrees.
The lift coefficient and drag coefficient do not change in the comparison between the cases before and after control when AOA is 0 degrees and 10 degrees. The analysis on the lift coefficient and drag coefficient shows that the flow is improved with the control. Smaller vortices are filled with the large separated area which is divided by the jet generated by split when the AOA is 20 degrees. Numerical results show that the control method has little negative influence on the airfoil performance at small AOAs. The results show that the separation area increases with increase of the AOA and the large separation area appears on the airfoil suction surface at AOA equal to 20 degrees. Good agreement was obtained between the comparison of the experimental and numerical results.
S809 airfoil was investigated experimentally and numerically with different operating conditions including cascade without control, cascade with slots that generate jets with AOAs of 0 degrees, 10 degrees, 15 degrees and 20 degrees. A new flow control approach called split blade is applied on the S809 airfoil in the present study.