Elam, Dana (2012) A direct numerical simulation of dielectric barrier discharge (DBD) plasma actuators for turbulent skin-friction control. PhD thesis, University of Warwick.

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Abstract

Turbulent skin-friction control is the subject of much research and the use of transverse (spanwise) oscillating motions offers the means of obtaining a significant reduction in skin-friction. Dielectric barrier discharge (DBD) actuators can be used to generate spanwise oscillating waves but the difficulty in placing a sensor in the area of plasma gives rise to problems in recording near-wall velocities. A modified version of the Shyy et al. (2002) DBD model was integrated into a direct numerical simulation (DNS). This numerical model was used in a series of two-dimensional simulations, in initially quiescent ow, and the results were compared to results reported from experimental investigations. A close affinity was found confirming that the DBD model is satisfactory. Both a temporal and a spatial, spanwise oscillating ow were investigated. Only one plasma profile was investigated. Three actuator spacings were investigated. Only the largest actuator spacing resulted in a gap between each plasma profile that was larger than the plasma profile width itself. A spatially uniform plasma configuration produced larger DR% than spanwise wall oscillation for both spatial and temporal waves, maximum DR = 51% compared to a DR = 47% for a spanwise wall oscillation. Increased skin-friction reductions originated from the displacement of the Stokes layer. The spatial wave produced lower skin-friction values than temporal waves for all the configurations. For both spatial and temporal waves the performance of the discrete configurations in producing an overall skin-friction reduction decreased with increasing actuator spacing. Using both temporal and spatial waves, the configuration with the largest spacing, which is relatively small, did not produce a drag reduction for any case that was tested.

Item Type:	Thesis or Dissertation (PhD)
Subjects:	T Technology > TA Engineering (General). Civil engineering (General)
Library of Congress Subject Headings (LCSH):	Frictional resistance (Hydrodynamics), Actuators, Turbulence
Date:	June 2012
Institution:	University of Warwick
Theses Department:	School of Engineering
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Chung, Yongmann M.
Extent:	xix, 190 leaves : ill., charts
Language:	eng
URI:	http://wrap.warwick.ac.uk/id/eprint/49964

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