Multi-DBD actuator
with floating interelectrode
for aerodynamic control
Janusz Podliński, Artur Berendt, Jerzy Mizeraczyk
Centre for Plasma and Laser Engineering
The Szewalski Institute of Fluid-Flow Machinery
Polish Academy of Sciences
Gdańsk, Poland
Outline

Dielectric Barier Discharge (DBD) plasma actuators
• Applications
• Design

Our investigations
• Electrode shape
• Electrode at floating potential
• Multi-DBD plasma actuator

Summary
2
DBD plasma actuators
DBD plasma actuator for flow modification
Actuator OFF
Flow
Actuator ON
Flow visualisation in an aerodynamic channel
with a DBD plasma actuator
3
DBD plasma actuators
DBD plasma actuator placed on an aerodynamic element
can influence on:
• Boundary layer transition
• Wing tip vortex
• Leading and trailing flow separation
DBD plasma actuators can change parameters of the
airfoils
• Lift force increase
• Drag force decrease
• Noise reduction
4
DBD plasma actuators
Top-side view of the „classic” DBD plasma actuator
Cross-section of the „classic” DBD plasma actuator
5
Our investigations
Experimental set-up
for DBD discharge parameters and flow measurements by PIV
6
Our investigations
Classic DBD plasma actuators
Without electrode gap
With electrode gap 20 mm
Up-p=24 kV; Ip=500 mA; f =1,5 kHz
Up-p= 48 kV; Ip=20 mA; f =1,5 kHz
7
Saw-like electrodes for DBD plasma actuators
Saw-like electrode
Example of saw-like electrode
DBD plasma actuators
with smooth and saw-like
electrodes
Smooth electrode
Electrode gap 20 mm
Up-p = 52 kV,
f = 1.5 kHz
The discharge for actuators with smooth
and saw-like electrode
Effect of saw-like electrode
 DBD starts at lower voltage
 More uniform discharge along electrodes
8
Saw-like electrodes for DBD plasma actuators
DBD plasma actuators with smooth and saw-like electrodes
Flow velocity field measured by PIV
Maximum flow generated by the actuators
with smooth and saw-like electrodes
(d – distance between electrodes in mm)
Effect of saw-like electrode
 Higher flow velocities generated by DBD
9
Multi-discharge plasma actuators
Schematic design
‘Classic’ Multi-DBD for actuators
Double DBD plasma
actuator possible
Multi-DBD with floating interelectrodes for actuators
10
Multi-DBD actuator with floating interelectrodes
Discharge visualisation - top view
Length of all electrodes: 80 mm
High voltage electrode width: 10 mm
HV to floating interelectrode distance: 0 mm
Grounded (1) to HV electrode distance: 0 mm
Floating interelectrode width: 4 mm
Floating to grounded (2) electrode distance: 4 mm
Grounded electrode width: 3 mm
High voltage: Upp = 32 kV, f = 1.5 kHz
11
Multi-DBD actuator with floating interelectrodes
Time-averaged streamlines
Time-averaged streamlines of an airflow induced
by the multi-DBD actuator with saw-like floating interelectrodes
Airflow velocity m/s
Dielectric: glass plate – 2 mm thick
Length of HV and grounded electrodes: 50 mm
Length of floating interelectrodes: 45 mm
High voltage electrodes width: 15 mm
HV and FL interelectrodes in optimum position
High voltage: Upp = 32 kV, f = 1.5 kHz
Floating interelectrodes width: 3 mm
Floating to grounded electrode distance: 6 mm
Grounded electrodes width: 3 mm
Grounded to floating electrode distance: 13 mm
12
Experimental set-up
for leading edge flow separation control
Wind tunnel
NACA 0012 model:
• Chord 200 mm
• Span 595 mm
• Multi-DBD actuator
with saw-like floating
interelectrode
Test section: 0.6 m x 0.46 m – 1.5 m long,
Velocity  100 m/s, Turbulence level  0.1 %
13
Leading edge flow separation control - results
Time-averaged flow velocity fields measured by PIV method
Multi-DBD plasma actuator with saw-like floating
interelectrode for leading edge flow separation control
Plasma OFF – separated airflow
U0 = 15 m/s
Incidence = 11o
Chord: 200 mm
Re = 200 000
Applied HV:
UHV = 15 kV
fHV = 1.5 kHz
Plasma ON - airflow reattachment
U0 = 15 m/s
Incidence = 11o
Chord: 200 mm
Re = 200 000
14
Summary
The DBD with saw-like electrodes:
•
Lower onset voltage,
•
More uniform discharge along electrodes,
•
Higher airflow velocities than the DBD with smooth
electrodes.
The multi-DBD actuator with floating interelectrodes:
•
Plasma generation on a large area of the dielectric surface,
•
Maximum airflow velocity over 10 m/s ,
•
Attractive for aerodynamic applications.
15