| Description |
xii, 93 leaves : illustrations (some color) ; 29 cm |
| Summary |
"A plasma actuator was operated at altitudes from 0 to 18288 meters to determine the mechanisms leading to decreased force production at low pressures. The actuator was driven with a 5 kHz sine wave and a peak to peak voltage of 13.4 kV at pressures of 760, 429, 321, 226, and 88 Torr. A passive measurement technique called the capacitive V-dot probe was adapted to the actuator in order to resolve the spatiotemporal evolution of the surface potential and electric field on the dielectric surface. At low pressures up to 20 times more plasma is present than at atmospheric conditions. Average force production is calculated and shown to decrease at lower pressures due to the fact that up to 88% of the plasma is created in regions where the electric field is approximately zero. The calculated average body force shows a slight increase up to a pressure of 429 Torr before trending to zero at lower pressures. Performing a power analysis shows that as pressure is decreased more power is used creating plasma than accelerating it, leading to a decrease in efficiency"--Abstract, leaf iii. |
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