On the Active and Passive Flow Separation Control Techniques over Airfoils

Abstract

Abstract. In the present work, recent advances in the field of the active and passive flow separation control, particularly blowing and suction flow control techniques, applied on the common airfoils are briefly reviewed. This broad research area has remained the point of interest for many years as it is applicable to various applications. The suction and blowing flow control methods, among other methods, are more technically feasible and market ready techniques. It is well established that the uniform and/or oscillatory blowing and suction flow control mechanisms significantly improve the lift-to-drag ratio, and further, postpone the boundary layer separation as well as the stall. The oscillatory blowing and suction flow control, however, is more efficient compared to the uniform one. A wide range of parameters is involved in controlling the behavior of a blowing and/or suction flow control, including the location, length, and angle of the jet slots. The oscillation range of the jet slot is another substantial parameter.

Sterowanie poprzeczne bezzałogowym statkiem powietrznym za pomocą zaburzaczy warstwy przyściennej

“…5. Układ wykorzystujący technikę "synthetic jet": (a) -z tłoczkiem [5], (b) -z membraną [4] Jedną z grup generatorów aktywnych są układy sterowania przy użyciu techniki "synthetic jet" (rys. 5).…”

Effect of varying frequency of a synthetic jet on flow separation over an airfoil

“…Over the past few decades, considerable effort has been devoted to drag reduction of airfoils using various passive and active control strategies. [5][6][7][8] Passive control can include vortex generators such as trip wires and surface roughness to delay flow separation while active control uses steady or periodically excited devices (e.g., actuators) that can be operated to achieve desired outcomes. 9 In many applications, active control devices are preferred because of their flexibility in off-design conditions and they do not introduce a drag penalty common with passive control devices permanently mounted on the airfoil.…”

Cavitation control using passive flow control techniques

“…Active controls include wall temperature increase, dynamic surface modification by deformation or movable parts, and injection or flow oscillation using blowing, suction, and synthetic jets. 24 This article aims to review studies focused on passive flow controls applied to cavitation. Among these, VGs are regarded as the most effective and simplest technique and have been used in many applications such as airfoils, wind turbine blades, swept wing, and heat exchangers.…”