Over the past few decades, surface dielectric barrier discharge (SDBD)
actuators have been studied extensively as aerodynamic flow control devices. There
has been extensive research on producing SDBD plasmas through excitation by
sinusoidal high voltage in low-speed flows, resulting in local acceleration of
the flow through the electrohydrodynamic (EHD) effect. However, high-speed flow
control using SDBD actuators has not been considered to the same extent.
Control through thermal perturbations appears more promising than using EHD
effects. SDBDs driven by nanosecond repetitively pulsed (NRP) discharges (NRP SDBDs)
can produce rapid localized heating and have been used to produce better flow
reattachment in high-speed flows. While surface actuators based on NRP DBDs
appear promising for high-speed flow control, the physics underlying the
plasma/flow coupling are not well understood and the actuators have yet to be
fully characterized or optimized. In
particular, methods for tailoring the plasma characteristics by varying the
actuator’s electrical or geometrical characteristics have not been thoroughly
explored.<div>In the current work, NRP SDBD
actuators for control of high-speed flows are developed and characterized. As
discussed previously, it is believed that the mechanism for high-speed flow
control by these plasmas is thermal perturbations from rapid localized heating.
Therefore, the goal is to design actuators that produce well-defined
filamentary discharges which provide controlled local heating. The electrical
parameters (pulse duration, PRF, and polarity) and electrode geometries are
varied and the optimal configurations for producing such plasma filaments over
a range of ambient pressures are identified. In particular, single and double
sawtooth shaped electrodes are investigated since the enhanced electric field
at the electrode tips may permit easier production of “strong” (i.e. higher
temperature) filaments with well-defined spacing, even at low pressure.
Time-resolved measurements of the gas temperature in the plasma will be
obtained using optical emission spectroscopy (OES) to assess the thermal
perturbations produced by the actuators. To the author’s knowledge, these will
be the first such measurements of temperature perturbations induced by NRP
SDBDs. The plasma structure and temperature measurements will be correlated
with schlieren visualization of the shock waves and localized flow field
induced by the discharges. Finally, the optimized actuators will be integrated
into a high-speed flat plate boundary layer and preliminary assessment of the
effect of the plasma on the boundary layer will be conducted.<br></div>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/7762148 |
| Date | 10 June 2019 |
| Creators | Aarthi Devarajan (5930600) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/Development_of_plasma_actuators_for_high-speed_flow_control_based_on_nanosecond_repetitively_pulsed_dielectric_barrier_discharges/7762148 |
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