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FLOW PHYSIC OF ACTIVE CONTROL WITH COUNTER-ROTATING CONTINUOUS JETS ON A RAMP

Christophe Cuvier
Univ Lille Nord de France F-59000 Lille, EC Lille, Laboratoire de Mecanique de Lille (UMR 8107) Boulevard Paul Langevin, 59655 Villeneuve d'Ascq Cedex, France

Jean-Marc Foucaut
Laboratoire de Mécanique de Lille, UMR CNRS 8107 Bv Paul Langevin, Cité Scientifique F-59655 Villeneuve d'Ascq, France; Laboratory for Turbulence Research in Aerospace and Combustion (LTRAC) Monash University, VIC 3800 Australia

Caroline Braud
Univ Lille Nord de France, CNRS, Laboratoire de Mecanique de Lille (UMR 8107) Boulevard Paul Langevin, 59655 Villeneuve d'Ascq Cedex, France

Michel Stanislas
Laboratoire de Mécanique de Lille, UMR CNRS 8107 Bv Paul Langevin, Cité Scientifique F-59655 Villeneuve d'Ascq, France; Laboratory for Turbulence Research in Aerospace and Combustion (LTRAC) Monash University, VIC 3800 Australia

Résumé

In this study, the flow reorganisation, given by continuous jets vortex generators (VGs) which controls the separation induced by a 22° flap on a ramp, was investigated through streamwise 2D2C PIV measurements at mid-span of the model. The VGs are set in counter-rotating arrangement. The field of view follows the wall surface. Its height is about 28.7 cm above the wall and its curvilinear length is about 94 cm, so that it contains all the separation bubble without control. Four 2k*2k cameras are used to keep a relatively good spatial resolution with this very large field. The separation is totally suppressed by the control configuration under study. The accessible Reynolds stresses with the PIV plane are presented and compared to the ones of the uncontrolled case. For the controlled flow, the three Reynolds stresses (u'2, v'2, u'v') exhibit a region of high levels which develops above the flap and which is similar to the high turbulence region which develops above the bubble border for the uncontrolled case. However, its intensity is highly reduced for the controlled flow and it is closer to the wall. The same is true for the production terms which indicates that the control applied here does not suppress totally the shear layer. It just reduces its intensity and squeezes it against the wall.