Experiments on the transition from the steady to the oscillatory Marangoni-convection of a floating zone under reduced gravity effect

Chun, Ch.-H.; Wuest, Walter

doi:10.1016/0094-5765(79)90056-0

Cited by 216 publications

(61 citation statements)

References 3 publications

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“…However, when DT ¼ T h À T c exceeds some critical value DT cr , instability sets in and gives rise to a number of time-dependent three-dimensional flow regimes. It was first experimentally observed by Schwabe and Scharmann [1] and by Chun and Wuest [2].…”

Section: Introductionmentioning

confidence: 92%

The Stability of a Thermocapillary-Buoyant Flow in a Liquid Bridge with Heat Transfer Through the Interface

Watanabe

Melnikov

Matsugase

et al. 2014

Microgravity Sci. Technol.

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a b s t r a c tThe hydrodynamic stability of a thermocapillary flow in a finite-size liquid bridge, with a non-deformable interface, heated from above and surrounded by a passive gas is examined by means of three-dimensional direct numerical simulations. Convective flow in 1 cSt silicone oil with Pr ¼ 18 is driven by combined effects of buoyancy and thermocapillary forces. Effects of the interfacial heat exchange on hydrothermal stability of the bulk flow are evaluated for various external thermal conditions in the gas phase. Cooling the interface can significantly shift the bifurcation point where the thermocapillary flow becomes oscillatory. If the Biot number Bi, which is a measure of the rate of the heat exchange, is not large, the effect of the interfacial heat flux can be either stabilizing or destabilizing, depending on both the temperature profile in the gas and the height of the liquid bridge. For a high value of heat loss rate, stabilization occurs regardless of the temperature distribution in the ambient gas. Various flow regimes are identified, and detailed stability maps are made for the flow under the considered ambient thermal conditions. It was found that the critical azimuthal mode of the flow changes according to the surrounding conditions in the gas phase. Observations have revealed three distinct azimuthal modes: m ¼ 0 (critical for a long liquid bridge at small Biot numbers), m ¼ 1 and m ¼ 2. Any mode change of the flow is accompanied by an abrupt change of the frequency of temperature oscillations.

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Section: Introductionmentioning

confidence: 92%

The Stability of a Thermocapillary-Buoyant Flow in a Liquid Bridge with Heat Transfer Through the Interface

Watanabe

Melnikov

Matsugase

et al. 2014

Microgravity Sci. Technol.

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“…During an experiment, typically the temperature difference between the end supports is maintained by heating one disk and cooling the other one, with respect to the ambient temperature, with symmetrical temperature ramps. When the Marangoni number is increased a first transition from the axisymmetric to the three-dimensional pulsating regime is observed for Ma= Ma c 1 .…”

Section: Experimental Techniquementioning

confidence: 98%

“…If the Marangoni number is further increased a travelling wave regime is established, characterized by rotating temperature spots along the free surface of the liquid bridge (for Ma = Ma c 2 > Ma c 1 The different behaviour in the pulsating and rotating regimes are more evident in the CCD images, due to the fact that the video acquisition rate is 25 fps (so that there are about 25 frames in each period). The temperature disturbances are evaluated in a post-analysis phase by subtracting, from the surface temperature distribution, the timeaveraged surface temperature field T o (z,) obtained integrating the experimentally measured surface temperature distribution over the period  of the oscillations.…”

Section: Experimental Techniquementioning

confidence: 99%

“…Experiments performed on ground and in microgravity conditions and numerical studies on the subject have been dedicated to the analysis of the transition from the steady axisymmetric toroidal flow to the threedimensional oscillatory flow; this last is established in non isothermal liquid bridges of high Prandtl number liquids when a critical temperature difference across the liquid bridge is exceeded [1][2][3][4][5][6][7]. In particular, recent numerical results, substantiated by experiments performed on ground with a micro-scale apparatus [8,9], have pointed out that, when the temperature difference across the liquid bridge is increased, the flow exhibits two transitions.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Geometrical Aspect Ratio on the Oscillatory Marangoni Convection in Liquid Bridgesum

2000

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This version is available at https://strathprints.strath.ac.uk/62649/ Strathprints is designed to allow users to access the research output of the University of Strathclyde. Unless otherwise explicitly stated on the manuscript, Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Please check the manuscript for details of any other licences that may have been applied. You may not engage in further distribution of the material for any profitmaking activities or any commercial gain. You may freely distribute both the url (https://strathprints.strath.ac.uk/) and the content of this paper for research or private study, educational, or not-for-profit purposes without prior permission or charge.Any correspondence concerning this service should be sent to the AbstractOscillatory Marangoni convection in silicone oil liquid bridges is investigated by threedimensional, time-dependent numerical solutions of the model equations and by micro-scale experimentation. The field equations are numerically solved with threedimensional control volume methods in a staggered cylindrical non-uniform grid. Two experimental configurations are utilized: 1) the two disks sustaining the bridges are made of copper, their temperatures are controlled with Peltier elements, the flow field in a vertical section is visualized by tracers illuminated by a laser light cut in the meridian plane and four fine temperature sensors are inserted axially from the hot disk into the liquid bridge; 2) the lower disk is made of copper and the upper one is made of transparent glass, heated by an electrical resistance, for visual measurements in a cross section orthogonal to the liquid bridge axis. The surface temperature distribution is measured by an infrared thermocamera. It is shown that the flow field organization, depending on the critical wave number, is related to the geometrical aspect ratio of the liquid bridge and that smaller is the aspect ratio, larger is the critical wave number and more complex the flow-field structure. For each aspect ratio considered, the flow field exhibits a first transition from the axysymmetric steady to a standing wave instability model and then a second transition from the standing wave to the travelling wave regime. The influence of buoyancy effects on the oscillatory Marangoni flow organization is investigated by heating the liquid bridges either from above or from below.

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“…When the temperature difference exceeds a critical value, depending on the geometry, on the liquid properties and on the boundary conditions, the flow experiences a transition to an oscillatory and three-dimensional pattern. A number of experimental works on the subject have been performed, on ground and in microgravity conditions, by different investigators [2][3][4][5][6][7][8][9][10]. From the theoretical/numerical point of view oscillatory thermocapillary flows in liquid bridges have been investigated by the hydrodynamic stability theory [11,12].…”

Section: Introductionmentioning

confidence: 99%

Flight results on marangoni flow instability in liquid bridges

et al. 2000

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Experiments on the transition from the steady to the oscillatory Marangoni-convection of a floating zone under reduced gravity effect

Cited by 216 publications

References 3 publications

The Stability of a Thermocapillary-Buoyant Flow in a Liquid Bridge with Heat Transfer Through the Interface

The Stability of a Thermocapillary-Buoyant Flow in a Liquid Bridge with Heat Transfer Through the Interface

Influence of Geometrical Aspect Ratio on the Oscillatory Marangoni Convection in Liquid Bridgesum

Flight results on marangoni flow instability in liquid bridges

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