Numerical study of blowing and suction slot geometry optimization on NACA 0012 airfoil

Abstract

The effects of jet width on blowing and suction flow control were evaluated for a NACA 0012 airfoil. RANS equations were employed in conjunction with a Menter's shear stress turbulent model. Tangential and perpendicular blowing at the trailing edge and perpendicular suction at the leading edge were applied on the airfoil upper surface. The jet widths were varied from 1.5% to 4% of the chord length, and the jet velocity was 0.3 and 0.5 of the free-stream velocity. Results of this study demonstrated that when the blowing jet width increases, the lift-to-drag ratio rises continuously in tangential blowing and decreases quasi-linearly in perpendicular blowing. The jet widths of 3.5% and 4% of the chord length are the most effective amounts for tangential blowing, and smaller jet widths are more effective for perpendicular blowing. The lift-to-drag ratio improves when the suction jet width increases and reaches its maximum value at 2.5% of the chord length.

On the Active and Passive Flow Separation Control Techniques over Airfoils

“…Predetermined active flow control includes uniform and non-uniform energy expenditure, regardless of the state of the flow. Reactive flow control is a particular active flow control in which the power expenditure of controllers is regularly tuned by measured parameters via in situ sensors [8,[16][17].…”

“…The blowing at the trailing edge, however, can enhance the lift, particularly by using smaller oscillation range. Hence, perpendicular suction at the leading edge and tangential blowing at the trailing edge are the best locations for suction and blowing jet slots [17,[24][25].…”

“…The effects of center suction and tip suction on the streamlines behind the wing are shown in figures 3 and 4 [24], respectively. In another study, Yousefi et al [25] and Yousefi and Saleh [17] investigated the effects of suction and blowing jet width on the aerodynamic characteristics of a NACA 0012 airfoil. It was found that the jet width of about 3.5%~4% of the chord length is optimum for tangential blowing, while for perpendicular blowing smaller jet widths are more efficient.…”

“…The optimum jet width is determined to be 2.5 percent of the chord length [25] in order to maximize the aerodynamic performance. However, the effects of the jet dissipate before it reaches the trailing edge of the airfoil if the jet width is not adequate.…”

Understanding boundary layer suction and its e ect on wings - A review

“…Kianoosh et al [21] observed that when a suction perpendicular to the ow is used, not only does the L/D ratio improve but the stall angle also increases, in the case of a NACA 0012 airfoil the stall angle improved from 14 0 to 22 0 . The hole width also had a direct e ect on the L/D ratio, where the increase in the hole width augmented the L/D ratio and delayed the separation further downstream [21].…”