Airfoil Flow Control Using Blowing And Suction

There are many engineering structures working with wind power.For example,the aircraft flies depending on the lift force generated by the wing,and the blades of wind turbine convert the kinetic energy of wind to electricity.As we all know,the wind contains enormous energy and development potential.In nature,the low-speed wind exists in many regions and it normally covers a longtime domain.The energy cannot be collected effectively by wind turbine if the wind velocity is smaller than the cut-in speed.To extract energy from low-speed wind,the study focuses on the improvement of aerodynamic performance on low Reynolds number airfoil using blowing and suction method.The aerodynamic performance of the airfoil can be improved by using jet control to change the flow field around it.The jet control is divided into active control and passive control,and this experiment adopts active jet control.The experiment model NACA0012 has a chord length(c)of 200mm,and a span length(b)of 300mm.The angle of attack(?)varies from 0oto 18o.There are three rows of holes on the suction surface,near the leading and trailing edge,respectively,which are used to achieve the blowing and suction.Experiments are carried out under two Reynolds numbers,namely,Re=1×10~5 and Re=2×10~5,respectively.The non-dimensional jet momentum coefficient C_?is introduced and varies.Under the configurations of different jet positions and Reynolds numbers,lift force and drag force of airfoil are measured by load cell.The flow field near the suction surface is explored through surface oil-flow visualization to comprehend the underlying mechanism of flow control.Through experiments,when blowing at the position of x/c=0.2 and suction at the position of x/c=0.6,the lift coefficient and lift-to-drag ratio are maximum.The maximum lift-to-drag ratio increases 123%,the maximum lift coefficient increases 43%,and the maximum stall angle is delayed 5o.The results prove that blowing and suction control method is effective for improving the aerodynamic performance of the airfoil.