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OPEN AND CLOSED-LOOP EXPERIMENTS TO REATTACH A THICK TURBULENT BOUNDARY LAYER

Tamir Shaqarin
Univ Lille Nord de France Laboratoire de Mecanique de Lille (UMR 8107) Boulevard Paul Langevin, 59655 Villeneuve d'Ascq Cedex, France; Mechanical Engineering Department, College of Engineering Tafila Technical University JORDAN

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

Sebastien Coudert
Laboratoire de Mécanique de Lille, UMR CNRS 8107 Bv Paul Langevin, Cité Scientifique F-59655 Villeneuve d'Ascq, 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

Abstrakt

Open and closed-loop control experiments were successfully performed to reattach a thick turbulent boundary layer, thanks to large scales of the facility (i.e. wind tunnel Carlier & Stanislas (2005)). This extends to large Reynolds numbers and large time scales the range of flow conditions for which open and closed-loop control configurations were investigated for turbulent flow separation configurations. Experiments were performed at three Reynolds numbers based on the momentum thickness of the turbulent boundary layer, varying from Reθ ~ 7500 to 12600. First open-loop tests were conducted to identify the systems. They were found to behave like a first order linear one, with coefficients that need to be adapted depending on the Reynolds number. Then, simple controllers (Proportional-Integral and Linear Quadratic Regulator) were implemented in closed-loop configurations. They were able to significantly improve the reactivity of the system and consequently the cost of the control. A test of robustness was performed from variations of the free-stream velocity which highlights the need to improve it using more complex controllers.