Experimental study of separation bubble control behind a backward-facing step using plasma actuators

In this paper, controlling flow around a backward-facing step by means of a dielectric barrier discharge plasma actuator is experimentally investigated. The pressure distribution on the step surface as well as the natural oscillations of the flow in the shear layer at three different Reynolds numbers from 18,000 to 54,000 (based on the step height) are measured in the wind tunnel. Then, by installing plasma actuators at different positions, the changes in pressure distribution and the length of the separation bubble are investigated. It was found that for controlling the separation bubble and expediting the flow recovery process the best position for installation of the plasma actuator is the upstream of the separation point i.e., step tip edge. Installing the actuator inside the separation bubble has a relatively low effect on the separation zone length. In addition, the most effective way for exciting the shear layer is utilizing the unsteady actuation with an exciting frequency equal to the natural frequency of the vortex shedding.

[1]  J. Kitzhofer.  Volumetric measurements of the transitional backward facing step flow , 2011 .

[2]  Martiqua L. Post,et al.  Scaling Effects of an Aerodynamic Plasma Actuator , 2007 .

[3]  Mohamed Gad-el-Hak.  Flow Control: Contents , 2000 .

[4]  Pierre Gajan,et al.  Experimental Application of an Active Control Loop on Backward-Facing Step Flow. , 2005 .

[5]  Guillermo Artana,et al.  Active Control of a Backward Facing Step Flow With Plasma Actuators , 2014 .

[6]  T. Corke,et al.  Single dielectric barrier discharge plasma enhanced aerodynamics: physics, modeling and applications , 2009 .

[7]  Mohamed Gad-el-Hak.  Flow Control: Flow Control , 2000 .

[8]  Julio Soria,et al.  Particle image velocimetry measurements of a backward-facing step flow , 2002 .

[9]  M. Hasan.  The flow over a backward-facing step under controlled perturbation: laminar separation , 1992, Journal of Fluid Mechanics.

[10]  I. Tani,et al.  Experimental investigation of flow separation associated with a step or a groove. , 1961 .

[11]  B. Armaly,et al.  Experimental and theoretical investigation of backward-facing step flow , 1983, Journal of Fluid Mechanics.

[12]  Jagannath Rajasekaran,et al.  On the Flow Characteristics behind a Backward-facing Step and the Design of a New Axisymmetric Model for their Study , 2011 .

[13]  T. McLaughlin,et al.  Flow over a Backward-Facing Step Under Controlled- Plasma Actuator-Induced Perturbations , 2010 .

[14]  Andy P. Broeren,et al.  Iced-airfoil aerodynamics , 2005 .

[15]  E. W. Adams,et al.  Effects of the separating shear layer on the reattachment flow structure part 2: Reattachment length and wall shear stress , 1988 .

[16]  Shinji Honami,et al.  Dynamic Characteristics in a Control System of Backward Facing Step Flow by Vortex Generator Jets , 2004 .

[17]  F. Durst,et al.  The dynamics of the transitional flow over a backward-facing step , 2009, Journal of Fluid Mechanics.

[18]  N. Zurlo,et al.  Unsteady behavior of back-facing step flow , 2001 .

[19]  Mohamed Gad-el-Hak,et al.  Flow Control: Passive, Active, and Reactive Flow Management , 2000 .

[20]  Jerome T. Kegelman,et al.  Control of coherent structures in reattaching laminar and turbulent shear layers , 1985 .

[21]  H. Sung,et al.  Control of turbulent separated flow over a backward-facing step by local forcing , 1996 .

[22]  M. B. Bragg,et al.  Measurements in a leading-edge separation bubble due to a simulated airfoil ice accretion , 1992 .