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Region of parameters of synthetic jets
Broučková, Z. ; Šafařík, P. ; Trávníček, Zdeněk
This work presents a summary of parameters which are needed for the descriptionof synthetic jets. Examples from available literature are discussed. A reliability of severalformation criteria of these jets is also verified. Most of the criteria have similar character andgive reliable results - all chosen examples satisfy the criteria. It is shown that one of theinvestigated criteria is not very trustful.Furthermore, the measurements of velocity of the axisymmetric synthetic jet were performedby means of the Pitot tube and the Hot-Wire Anemometry. The results are in very goodaccordance with the ones from literature. Moreover, it was revealed that the decreasing of theReynolds number and the working point approaching towards the critical value on theboundary of formation lead to the gradual shortening of the reach of the jet.
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Experimental investigation of a control synthetic jet
Němcová, L. ; Kordík, Jozef ; Trávníček, Zdeněk ; Kopecký, V.
Synthetic jets were used in previous studies to control a continuous round air jet. This study focuses on the single synthetic jet, which is measured using Constant Temperature Anemometry (CTA) and Particle Image Velocimetry (PIV). Velocity profiles and frequency characteristics of the single synthetic jet are discussed and the velocity maps at frequencies of 30 Hz, 81 Hz and 190 Hz are presented. Finally, velocity, flow rate and momentum coefficients featured the present flow control are evaluated, and examples of actively controlled round air jet are put on. The results confirm efficiency of the present flow control method.
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The interaction of continual and synthetic jets
Broučková, Zuzana ; Trávníček, Zdeněk ; Šafařík, Pavel
This work deals with an interaction of continual and cross synthetic jets. Both jets are axisymmetric. All measurements have been performed in air by means of the Pitot tube and hot-wire anemometry. Flow visualization has been also performed. The possibility of flow control is shown and quantified. For the moderate momentum ratio, the mean jet deflection reasonably agrees with the momentum conservation.
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PIV measurement of synthetic jet array
Dančová, Petra ; Vít, Tomáš ; Kotek, M.
This paper describes PIV experiments of a synthetic jet array. This part of measurements is an important step of the general study of a channel flow which is affected by synthetic jet array with emphasis on low Reynolds numbers. The study is experimental. The experiments are performed with water as the working fluids, and PIV method is used.
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