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Vortex structures generated by dbd plasma actuator
Procházka, Pavel P.
This article 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 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 article 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.
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Colloquium Fluid Dynamics 2013, proceedings
Uruba, Václav ; Jonáš, Pavel
The purpose of the Colloquium is to bring together experts on theoretical and experimental fluid mechanics from the academic institutes, universities and other research and development establishments and to offer the opportunity to exchange and update information on the solved problems and to serve as a forum for discussion with leading scientists.
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Integral fluidic generator of microbubbles
Tesař, Václav ; Jílek, Miroslav
Very small gas bubbles dispersed in liquid are desirable in many applications. If smaller than 1 mm in diameter, they are called microbubbles. Until recently, the advantages they offer have been little usedbecause of generally low efficiency of microbubble generation methods. A solution was found in pulsating the gas flow into the submerged aerator by a fluidic oscillator. At present, the oscillator and aerator are separate devices. The flow pulsation is strongly damped in the connecting tubes. New solution presented in this paper relies on oscillator robustness and no need for maintenance, which allows integrating it with the aerator into a single body submerged in the liquid. Small bubble size requires driving frequency much higher than has been so far applied. The present paper shows some of the ways leading to high frequencies – in particular the use of dominant third harmonic of the basic switching frequency.
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Analytical and numerical approach to the airfoil stability computation
Chládek, Štěpán ; Horáček, Jaromír
The fluid structure interaction (FSI) represents an important task in many applications. This paper deals with interaction of airfoil and fluid flow and compares two possible ways of computation of the stability boundaries of the system. The airfoil has two degrees of freedom represented by translation h(t) and rotation a(t). The flow acts on the airfoil with aerodynamic forces depending on the flow velocity. Two methods for calculation of the critical flow velocity, when the airfoil loses aeroleastic stability, are described.
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Improvements of saltation model
Kharlamova, Irina ; Vlasák, Pavel
The present paper introduces a new model of a bed-load transport. The model simulates a particle motion in the channel with turbulent flow and rough bed. The effects of mutual interaction of conveyed particles with carrier liquid, with bed particles, and also with other conveyed particles are taken into account. The model predicts average saltation characteristics, e.g. saltation length and height, particles distribution in vertical direction, and mass rate of conveyed particles per unit area of channel bed.
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