0421381 - ÚT 2014 CZ eng D - Thesis
Procházka, Pavel P.
Vortex structures generated by plasma DBD actuator.
Ústav termomechaniky AV ČR, v. v. i. Defended: ČVUT FS. 29.10.2013. - Praha: ČVUT, FS, 2013. 103 s.
R&D Projects: GA ČR GAP101/10/1230
Institutional support: RVO:61388998
Keywords : plasma actuator * vortex * PIV
Subject RIV: BK - Fluid Dynamics

This dissertation thesis deals with the research of vortex structures generated by a plasma actuator. Plasma actuators belong to devices that can be used for active flow control. Plasma active flow control issues and historical development of this technology are outlined in the introduction. Plasma actuator construction features are described as well as its power source, which has to meet some special criteria. The velocity vector field is measured by a standard time-resolved PIV method, which is convenient for investigation of velocities in the actuator vicinity. Considering that actuator-generated-flow has periodical nature, data acquisition and data processing should obey some special procedures. Using methodology of phase-averaging is combined with computation of the individual phase of flow from POD modes of this dynamics phenomenon. Consequently, the coherent structure identification from the experimentally gained vector field is solved in this thesis. Well-known identification schemes as well as new algorithms especially adjusted for this purpose are used. The investigation methods provide a determination of coherent structure dynamics for different input parameters of the power source, e.g. voltage value or amplitude modulation frequency. Vortex structures are examined for in the case of a plasma actuator without presence of a free flow boundary layer. Plasma actuator flow control has been in the center of interest for the last two decades. However, one can find only a limited amount of information dealing with the physical principal of this phenomenon. The conclusion of this thesis is formulated to give an explanation of physical laws acting during generating, evaluating and decay vortex structures in a complex way to ensure that results could be apply in the future for more applicable research.
Permanent Link: http://hdl.handle.net/11104/0229635