Author: Rocco Arpa
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Denis Palmeiro
Publisher:
ISBN: 9780494823682
Category :
Languages : en
Pages : 198

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Single-dielectric-barrier-discharge (SDBD) plasma actuators have shown much promise as an actuator for active flow control. Proper design and optimization of plasma actuators requires a model capable of accurately predicting the induced flow for a range of geometrical and excitation parameters. A number of models have been proposed in the literature, but have primarily been developed in isolation on independent geometries, frequencies and voltages. This study presents a comparison of four popular plasma actuator models over a range of actuation parameters for three different actuator geometries typical of actuators used in the literature. The results show that the hybrid model of Lemire & Vo (2011) is the only model capable of predicting the appropriate trends of the induced velocity for different geometries. Additionally, several modifications of this model have been integrated into a new proposed model for the plasma actuator, introducing a number of improvements.

Author: Jinjun Wang
Publisher: Cambridge University Press
ISBN: 1107161568
Category : Science
Languages : en
Pages : 293

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Master the theory, applications and control mechanisms of flow control techniques.

Author: Karthik Naganathan
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Plasma actuators are active flow control devices used for vortex generation, momentum addition, and boundary layer attachment. The advantages of plasma actuators are that they are lightweight, quick to respond, and lack moving parts. Channel Dielectric Barrier Discharge actuators are a type of dielectric barrier discharge actuators in which the exposed electrode is placed in the bulk fluid to reduce viscosity effects. There are very few models that can predict the plasma forcing with good accuracy. These models however do not account for the geometric parameters such as the width of the electrode. This thesis discusses two numerical models, one built from a surface DBD model and one built from electrostatic modeling. The modified surface DBD model predicts exit velocity profiles similar to the experimental results. But it fails to account for some geometric parameters. The electrostatic model successfully captures the potential distribution asymmetry. The forcing function obtained by curve fitting the force distribution was adjusted to give reasonable velocity distribution when implemented as a source term in the CFD solver. The adjusted ES model predicted velocity contours and Reynolds number variation with good accuracy.

Author: Sylvain Grosse
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Author: Kazuo Shimizu
Publisher:
ISBN:
Category : Technology
Languages : en
Pages :

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Dielectric barrier discharge (DBD) plasma actuators are a technology which could replace conventional actuators due to their simple construction, lack of moving parts, and fast response. This type of actuator modifies the airflow due to electrohydrodynamic (EHD) force. The EHD phenomenon occurs due to the momentum transfer from charged species accelerated by an electric field to neutral molecules by collision. This chapter presents a study carried out to investigate experimentally and by numerical simulations a micro-scale plasma actuator. A microplasma requires a low discharge voltage to generate about 1 kV at atmospheric pressure. A multi-electrode microplasma actuator was used which allowed the electrodes to be energized at different potentials or waveforms, thus changing the direction of the flow. The modification of the flow at various time intervals was tracked by a high-speed camera. The numerical simulation was carried out using the Suzen-Huang model and the Navier-Stokes equations.

Author: Dana Elam
Publisher:
ISBN:
Category :
Languages : en
Pages :

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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.

Author: Marios Kotsonis
Publisher:
ISBN: 9789461911971
Category :
Languages : en
Pages :

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Author: Dmitry F. Opaits
Publisher:
ISBN:
Category :
Languages : en
Pages : 278

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Author: Dmitry Florievich Opaits
Publisher:
ISBN:
Category :
Languages : en
Pages : 139

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