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Marangoni effect

About: Marangoni effect is a research topic. Over the lifetime, 5336 publications have been published within this topic receiving 98562 citations. The topic is also known as: Gibbs–Marangoni effect.


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Journal ArticleDOI
15 Nov 1998
TL;DR: Experiments and simulations prove that marginal regeneration cannot be the result of thickness fluctuations, and that it is due to surface tension gradients between the film and its borders.
Abstract: Marginal regeneration is the rate-determining drainage mechanism in mobile vertical liquid films stabilized with surfactants. Mysels, Frankel, and Shinoda explained this process from (thermal) thickness fluctuations, like capillary waves. The Laplace underpressure in the Plateau border would exert a larger force on a thick, rather than on a thinner film element. This force unbalance would make film elements of different thicknesses move in opposite directions so that they are exchanged at the border. However, experiments and simulations prove that marginal regeneration cannot be the result of thickness fluctuations. Our alternative view is, that marginal regeneration is due to surface tension gradients between the film and its borders. Drainage of film elements into the lower Plateau border causes a local excess of surfactant, and thereby local differences in surface tension. This causes film elements to flow and generates the thickness differences between the absorbed and emerging film elements. The rates of the Marangoni flows reflect the surface dilational properties. This Marangoni effect is a consequence of the compression of the film surface when a film element flows into the lower Plateau border. Marginal regeneration is then a mechanism which returns the surfactant back into the film.

38 citations

Journal ArticleDOI
TL;DR: In this article, the authors studied the influence of thermocapillary forces on the natural convection of a Newtonian fluid contained in an open cavity, where the heated molecules of the fluid are allowed to enter the cavity region to cause the convection flow.

38 citations

Journal ArticleDOI
TL;DR: In this article, it was found that solitary waves, excited and sustained by Marangoni stresses, are very stable during interactions with others, keeping their original shapes and celerities after interactions, thus experiencing at most a phase shift.
Abstract: In Marangoni–Benard convection with mass transfer from gas phase to liquid phase, it is found that solitary waves, excited and sustained by Marangoni stresses, are very stable during interactions with others, keeping their original shapes and celerities after interactions, thus experiencing at most a phase shift. Both positive and negative phase shifts have been observed for different types of oblique interaction. A ‘‘critical’’ angle, at which zero phase shift occurs as a result of the interaction, has been defined to delineate regions of negative and positive phase shifts.

38 citations

Journal ArticleDOI
TL;DR: In this article, the effects of different beam geometries including circular, rectangular and diamond shapes on laser melting of metallic materials were investigated, and the finite volume method was used to simulate the transient effects of a moving beam.
Abstract: Laser melting is an important industrial activity encountered in a variety of laser manufacturing processes, e.g. selective laser melting, welding, brazing, soldering, glazing, surface alloying, cladding etc. The majority of these processes are carried out by using either circular or rectangular beams. At present, the melt pool characteristics such as melt pool geometry, thermal gradients and cooling rate are controlled by the variation of laser power, spot size or scanning speed. However, the variations in these parameters are often limited by other processing conditions. Although different laser beam modes and intensity distributions have been studied to improve the process, no other laser beam geometries have been investigated. The effect of laser beam geometry on the laser melting process has received very little attention. This paper presents an investigation of the effects of different beam geometries including circular, rectangular and diamond shapes on laser melting of metallic materials. The finite volume method has been used to simulate the transient effects of a moving beam for laser melting of mild steel (EN-43A) taking into account Marangoni and buoyancy convection. The temperature distribution, melt pool geometry, fluid flow velocities and heating/cooling rates have been calculated. Some of the results have been compared with the experimental data.

38 citations

Journal ArticleDOI
TL;DR: In this article, the effect of noncondensables (i.e., air) was studied by comparing convection in the liquid layer below a vapor space at pressures ranging from 4.8 kPa to 101 kPa, corresponding to air molar fractions ranging from 14% to 96%, respectively, under otherwise identical conditions.
Abstract: The convective flow in a layer of volatile silicone oil with a kinematic viscosity of 0.65 cSt confined to a sealed cavity with a transverse aspect ratio of 3.2 was visualized using particle pathlines and quantified by particle-image velocimetry at dynamic Bond numbers estimated to be of order unity and laboratory Marangoni numbers as great as 3600. The effect of noncondensables (i.e., air) was studied by comparing convection in the liquid layer below a vapor space at pressures ranging from 4.8 kPa to 101 kPa, corresponding to air molar fractions ranging from 14% to 96%, respectively, and silicone-oil vapor, under otherwise identical conditions. The results for convection at 101 kPa are in qualitative agreement with previous studies, and clarify the time-dependent flow observed at high Marangoni numbers. The results show that decreasing the relative air concentration increases the critical Marangoni numbers for transition between different flow states, even though the air concentration does not appear to ...

38 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023212
2022421
2021289
2020283
2019217
2018247