Stability of Subsonic Jet Flows

Козлов, В. В.; Grek, G. R.; Dovgal, A. V.; Litvinenko, Yu. А.

doi:10.4236/jfcmv.2013.13012

Cited by 12 publications

(7 citation statements)

References 13 publications

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“…These shear layer structures also became more organized as the jet density was reduced relative to the density of the ambient gas [8]. Both the flow dynamics and possible instabilities in the jet strongly depend on the conditions at the nozzle exit including the Reynolds number, nozzle geometry and initial velocity [6,11]. Hence it is often difficult to make general conclusions on flow structures of different jets.…”

Section: Introductionmentioning

confidence: 99%

Gas flow characteristics of a time modulated APPJ: the effect of gas heating on flow dynamics

Zhang

Sobota

Veldhuizen

et al. 2014

J. Phys. D: Appl. Phys.

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This work investigates the flow dynamics of a radio-frequency (RF) non-equilibrium argon atmospheric pressure plasma jet. The RF power is at a frequency of 50 Hz or 20 kHz. Combined flow pattern visualizations (obtained by shadowgraphy) and gas temperature distributions (obtained by Rayleigh scattering) are used to study the formation of transient vortex structures in initial flow field shortly after the plasma is switched on and off in the case of 50 Hz modulation. The transient vortex structures correlate well with observed temperature differences. Experimental results of the fast modulated (20 kHz) plasma jet that does not induce changes of the gas temperature are also presented. The latter result suggests that momentum transfer by ions does not have dominant effect on the flow pattern close to the tube. It is argued that the increased gas temperature and corresponding gas velocity increase at the tube exit due to the plasma heating increases the admixing of surrounding air and reduces the effective potential core length. With increasing plasma power a reduction of the effective potential core length is observed with a minimum length for 5.6 W after which the length extends again. Possible mechanisms related to viscosity effects and ionic momentum transfer are discussed.

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Section: Introductionmentioning

confidence: 99%

Gas flow characteristics of a time modulated APPJ: the effect of gas heating on flow dynamics

Zhang

Sobota

Veldhuizen

et al. 2014

J. Phys. D: Appl. Phys.

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“…The flame behaviour is correlated with the process of round free jet flattening and bifurcation in a transverse acoustic field [6]. Acoustic forcing of a slit burner flame was experimentally investigated in [5], and it was confirmed that the bifurcation of the jet due to acoustic forcing is basically a two-dimensional phenomenon.…”

Section: Diffusion Combustion Of Propane Round Microjetmentioning

confidence: 99%

“…However, this mechanism still remains unclear. The experimental studies [6][7][8][9][10][11][12] and other, where the influence of the initial conditions at the nozzle exit and acoustics on the development of round and plane microjets in the absence of combustion at low Reynolds numbers were investigated in detail, which made it possible to understand and explain some phenomena in the flame behaviour observed during propane combustion in these jets. The results of these studies are presented in this paper.…”

Section: Introductionmentioning

confidence: 99%

Stability of Subsonic Microjet Flows and Combustion

Козлов¹,

Grek²,

Katasonov³

et al. 2013

JFCMV

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Results of experimental studies of round and plane propane microjet combustion in a transverse acoustic field at small Reynolds numbers are presented in this paper. Features of flame evolution under the given conditions are shown. Based on the new information obtained on free microjet evolution, new phenomena in flame evolution in a transverse acoustic field with round and plane propane microjet combustion are discovered and explained.

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“…С другой стороны, профиль скорости на срезе сопла, например, круглой микроструи при диаметре выходного отверстия сопла d ≤ 1 мм и удлинении канала сопла l/d ≥ 100 практически всегда будет иметь параболический характер ее распределения. Все особенности структуры и характеристик развития круглой и плоской микроструй в зависимости от изменений начальных условий на срезе сопла и акустического воздей-ствия представлены в работах [8][9][10][11][12][13]. Воздействие поперечного акустического поля на круглую микрострую приводит к ее уплощению, она становится квазиплоской и подвержена синусоидальной неустойчивости, как классическая плоская струя [11].…”

Section: Introductionunclassified

“…Воздействие поперечного акустического поля на круглую микрострую приводит к ее уплощению, она становится квазиплоской и подвержена синусоидальной неустойчивости, как классическая плоская струя [11]. Другой важной особенностью механизма развития как круглой, так и плоской микроструи является ее бифуркация (раздвоение) в поперечном акустическом поле [10][11][12][13]. Процесс раздвоения синусоидально неустойчивой микроструи приводит к возникновению двух разбегающихся под определенным углом струй, каждая из которых представляет собой набор когерентных вихревых структур.…”

Section: Introductionunclassified