Aerodynamic modification of flow over bluff objects by plasma actuation

Particle image velocimetry and smoke visualization are used to study the alteration of the flow field in the wake of a bluff body by use of an alternating current (AC) surface dielectric barrier discharge. Staggered, surface, and buried electrodes were positioned on the downstream side of circular cylinders at conditions of ReD = 1 × 104−4 × 104 configured to impose a force due to the ion drift that is either along or counter to the free-stream flow direction. Smoke visualization and Particle Image Velocimetry (PIV) in the wake of the flow confirms that the configuration of the surface electrodes and operation of the discharge significantly alters the location of the flow separation point and the time-averaged velocity profiles in the near and distant wake. Measurements of the vibrational and the rotational temperature using optical emission spectroscopy on the N2 second positive system (C3Πu–B3Πg) indicates that the resulting plasma is highly non-equilibrium and discounts the possibility of a thermal effect on the flow separation process. The mechanism responsible for reduction or enhancement of flow separation is attributed to the streamwise force generated by the asymmetric ion wind—the direction of which is established by the electrode geometry and the local surface charge accumulated on AC cycles.

[1]  M. R. Malik,et al.  Ion wind drag reduction , 1983 .

[2]  Flow control with electrohydrodynamic actuators , 2001 .

[3]  T. Corke,et al.  Separation Control on HIgh Angle of Attack Airfoil Using Plasma Actuators , 2004 .

[4]  P. Stephen,et al.  Boundary Layer Flow Control With a One Atmosphere Uniform Glow Discharge Surface Plasma , 1998 .

[5]  Eric Moreau,et al.  Asymmetric surface dielectric barrier discharge in air at atmospheric pressure: electrical properties and induced airflow characteristics , 2005 .

[6]  Gabriel Font,et al.  Boundary Layer Control with Atmospheric Plasma Discharge , 2004 .

[7]  T. McLaughlin,et al.  Mechanisms and Responses of a Single Dielectric Barrier Plasma , 2003 .

[8]  C. Laux,et al.  Optical Diagnostics and Radiative Emission of Air Plasmas , 1993 .

[9]  J. Roth,et al.  Electrohydrodynamic Flow Control with a Glow-Discharge Surface Plasma , 2000 .

[10]  Guillermo Artana,et al.  Control of the near-wake flow around a circular cylinder with electrohydrodynamic actuators , 2003 .

[11]  U. Kogelschatz.  FUNDAMENTALS AND APPLICATIONS OF DIELECTRIC-BARRIER DISCHARGES , 2000 .

[12]  E. Moreau,et al.  Plasma actuators for airflow control: measurement of the non-stationary induced flow velocity , 2005 .

[13]  J. Roth,et al.  Aerodynamic flow acceleration using paraelectric and peristaltic electrohydrodynamic effects of a One Atmosphere Uniform Glow Discharge Plasma , 2003 .

[14]  Eric J. Jumper,et al.  Mechanisms and Responses of a Single Dielectric Barrier Plasma Actuator: Plasma Morphology , 2004 .

[15]  C. Chun,et al.  The wake flow control behind a circular cylinder using ion wind , 2003 .

[16]  Gabriel Font,et al.  Boundary Layer Control with Atmospheric Plasma Discharges , 2006 .

[17]  G. M. Colver,et al.  Drag reduction by dc corona discharge along an electrically conductive flat plate for small Reynolds number flow , 1997 .

[18]  E. Jumper,et al.  Mechanisms and Responses of a Dielectric Barrier Plasma Actuator: Geometric Effects , 2004 .