European Drag Reduction and Flow Control Meeting – EDRFCM 2010 September 2–4, 2010, Kyiv, Ukraine FLOW CONTROL ON WING BY MEANS OF TRAPPED VORTEX CELL D. Lasagna, G. Iuso Dipartimento di Ingegneria Aeronautica e Spaziale, Politecnico di Torino, Corso Duca degli Abruzzi, 10129 Torino, Italy
[email protected] INTRODUCTION A flow control strategy which has not received a great attention is the so called ”trapped vortex cav- ity”, (TVC). The proposed technique consists in a cavity accommodated on the upper surface of the airfoil, with a shape optimized for trapping a vortex. Under appropriate conditions, a steady, large vor- tical structure forms in the cavity creating a ”moving interface”. The vortex cell causes the boundary layer flowing past it to remain more filled, moving the separation point dowstream. The goal is to in- crease the aerodynamic performances of the wing, both at low and high angles of attack. Most of the work on this subject, see [1], has been done in the framework of the VortexCell2050 project, even if pre- vious implementation of this technique are known, such as the EKIP aircraft [2] and the Kasper wing [3]. Both numerical and experimental investigations have shown that the success of this flow control technique tightly depends on the stabilization of the vortex. In fact theoretical investigations [4] have shown that a trapped vortex can have a limited stability region, i.e. it is unstable and cannot be kept trapped if some control in the cavity region is not exerted. Several authors have demonstrated experimentally [5] and numerically [6] the positive effects of suction for controlling the stability of the vortex in the cavity.