Browsing by Subject "Aerodynamic flow control"

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    An investigation of dielectric barrier discharge based plasma actuator designs with enhanced performance in active flow control
    (2013-04) Guo, Song
    This work presents an investigation of various dielectric barrier discharge based aerodynamic plasma actuator designs, in order to make plasma actuators more efficient in the aerodynamic active flow control. Based on the electric wind generation schemes of the AC signal driven plasma actuator, two features intended to explore the controlling of the accumulated surface charges are introduced in the new plasma actuator design: 1. By adding a diode-driven third electrode downstream of the discharge region; 2. By depositing a hundred-nanometer-thick layer of semiconductor material on the dielectric surface. Both measurement of thrust and flow separation control indicate that the new designs have better performance than traditional plasma actuators. Different geometries have been tested by varying the thickness of the hydrogenated amorphous silicon layer and the location of the third electrode. This aims to determine an optimized configuration of the plasma actuator based on performance. More experiments have been performed, focusing on exploration of the physics behind the two added features. Intensified CCD camera images of microdischarges have been recorded to illustrate the effects of added features. Also, surface charge distribution measurements have been performed, which reveal that the third electrode has an influ-ence on the distribution of the deposited surface charges and the semiconductor surface helps to move the surface charges. The effects of the added features have also been studied numerically. The effects in the visible plasma region are simulated using MATLAB and the effects of the downstream region are simulated by a model implemented in COMSOL Multi-physics. The computa-tional results have well explained the observations of enhanced the plasma actuator per-formance.