1. Parametric Optimization of Single Dielectric Barrier Discharge (SDBD) Plasma Actuators*
Alexey V. Kozlov, Flint O. Thomas †
20th Aerospace and Mechanical Engineering Graduate Student Conference
Notre Dame, Indiana 19 October 2006
Supported by NASA Langley NAG
by NASA Langley Research Center
†Advisor

2. Motivation and Objectives
There has been growing interest in flow control using dielectric barrier discharge plasma actuators in recent years. However, studies regarding optimization of plasma actuators are relatively scarce.
The Center for Flow Physics and Control at Notre Dame is involved in the development of single dielectric barrier discharge plasma actuators (SDBD) for several aerodynamic applications of active separation control.
Flow control experiments show that the performance of present-day plasma actuators at high freestream velocities (high Reynolds numbers) is not enough.
A primary objective is to optimize single dielectric barrier discharge plasma actuator toward growing demands of the flow control science. .

3. Overview of SDBD Plasma Actuators
DBD discharge consists of numerous short-time small-scale microdischarges (streamers) distributed randomly in time and in surrounding air volume
Plasma volume charge in the presence of an electric field, E*, results in a body force, Fb.
Plasma formation is accompanied by a coupling of directed momentum to the surrounding air.

4. Dielectric barrier dischage
Uniform glow
Filamentary form

5. Plasma body force, power dissipation and maximum induced velocity estimation

6. The Plasma Generation Circuit
High voltage for the excitation of the plasma actuators is obtained
from the secondary coil of the transformer.
Anti noise filter suppresses radio frequency electromagnetic noise radiation
from high voltage wires. Accurate hot-wire measurements in the vicinity
of the plasma discharge are now possible.

7. Schematic of the experimental setup for thrust measurement

8. Power dissipation versus applied voltage dielectric material: quartz glass (dielectric constant 3.7) dielectric thickness 1/4”, encapsulated electrode width 2”

9. Thrust versus applied voltage

10. Thrust versus power dissipation
X/D = 10, y/D =2

11. Relation between voltage, optimal frequency and thrust

12. Voltage waveform comparison
Thrust vs. voltage for ramp (sawtooth) and sinusoidal waveforms

13. Pitot probe velocity measurements
Plasma induced velocity profile

14. Multiple actuators Thrust vs. applied voltage
f =48 Hz
Thrust vs. applied voltage
Plasma induced velocity profile

15. Summary & Focus of Current Work
Optimize plasma actuator design by consideration of:
Increase of dielectric thickness and applied voltage and using optimal frequency greatly improve plasma actuator performance.
(2) Experiments clearly show the benefit of using ramp (sawtooth) waveform.
Multiple actuators (plasma array) significantly increase the body force and plasma induced velocity.
Additional measurements to investigate the influence of the dielectric thickness on the optimal frequency and body force are planned.