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Showing papers on "Marangoni effect published in 1980"


Journal ArticleDOI
TL;DR: In this paper, verification of the existence of Marangoni convection on earth, the influence of gravity, oscillatory instability and the effects of forced convection by different modes of rotation (iso-, counter-and single-rotation) are discussed.

156 citations


Journal ArticleDOI
TL;DR: In this article, temperature profiles on the free surface of a floating zone are measured and discussed in connection with the onset of oscillatory instability of the Marangoni convection and the transition phenomena from steady to fully developed oscillatory convection.

116 citations


Journal ArticleDOI
TL;DR: In this article, a mathematical model consisting of the Navier-Stokes and thermal energy equations, together with the appropriate boundary conditions for both media, is presented to solve this boundary value problem, with the expansion parameter being the Marangoni number.
Abstract: The Marangoni phenomenon is shown to be the primary mechanism for the movement of a gas bubble in a nonisothermal liquid in a low-gravity environment. In such a two-phase system, local variations in surface tension at the bubble surface are caused by a temperature gradient in the liquid. Shearing stresses thus generated at the bubble surface lead to convection in both media, as a result of which the bubble moves. A mathematical model consisting of the Navier-Stokes and thermal energy equations, together with the appropriate boundary conditions for both media, is presented. Parameter perturbation theory is used to solve this boundary value problem, with the expansion parameter being the Marangoni number. The zeroth, first- and second-order approximations for the velocity, temperature and pressure distributions in the liquid and in the bubble, and the deformation and terminal velocity of the bubble are determined. Experimental zero-gravity data for a nitrogen bubble in ethylene glycol, ethanol, and silicone...

69 citations


Journal ArticleDOI
TL;DR: In this paper, the authors studied conditions for attaining a Poiseuille-type regime in a non-isothermal "capillary" channel under the combined action of pressure gradients, gravitational fields and surface tension gradients.

47 citations


Journal ArticleDOI
TL;DR: In this article, a general formalism is developed to study interfacial convective instability of two immiscible incompressible fluids, and a linear stability analysis is performed and restricted to pure longitudinal perturbations for long wavelengths.

45 citations


Journal ArticleDOI
TL;DR: In this article, the authors considered the possibility of unstable normal modes (l = 1, 2, 3) of deformation of a fluid drop immersed in an infinite amount of another liquid.
Abstract: The possibility of unstable normal modes (l= 1, 2, 3…) of deformation of a fluid drop immersed in an infinite amount of another liquid is considered. The instability is produced by Marangoni effects (gradients in interfacial tension) caused by mass transfer of surfactants or surface chemical reactions.For mass transfer of a single surfactant in the presence of a high surface tension, instabilities can be provoked by diffusion from outside into the drop if the outside diffusion coefficient is lower than the inside diffusion coefficient. For lower inside diffusion coefficients, modes below a certain l-value may be unstable for diffusion from outside into the drop, whereas modes above this l-value can only be unstable for the reverse direction of diffusion. For low surface tensions, instability can be provoked only by diffusion from outside into the drop; the critical threshold goes to zero when the surface tension goes to zero. The latter feature makes the model useful for conceptualisation of the distruption of fat droplets by detergents during cleansing processes, or of oil ganglia in porous rocks during tertiary oil recovery.Cytokinetic processes in the living cell can be roughly described by the present model by the introduction of an “effective surface tension” stemming from contractile elements in the ectoplasmic layer adjacent to the cell membrane. Hydrodynamic motion is coupled together with damped oscillations of enzyme concentrations in a simple enzyme cycle by means of enzymes producing contractile elements. The model gives interesting relations between phenomena such as chemotaxis (l= 1) and cell division (l= 2) and makes possible a simple mechanism for the mitotic clock. Some forms of cancer could be understood as anomalous narrowing of the thresholds found between the oscillatory marginal states (“clock states”) and the non-oscillatory marginal states (cell division) for the l= 2 mode.

24 citations


Journal ArticleDOI
TL;DR: The effect of solidification on the onset of surface tension driven convection in a reduced gravity environment is studied in this paper, where two simple but physically realistic configurations representing the solidification of a simple material are analyzed.

7 citations


Journal ArticleDOI
TL;DR: In this paper, the authors investigated the role of oscillatory instability in the onset of instability in mass transfer and found that it is correlated with violent interfacial turbulence or eruption, and that instability always takes place when the destabilizing Rayleigh effect and the stabilizing Marangoni effect are competing.
Abstract: Condition for the onset of interfacial turbulence in mass transfer is investigated by a linear stability analysis. In a previous paper, it was revealed that inclusion of the Rayleigh effect as well as the Marangoni effect into analysis alters the stability limit and removes the contradiction between many experimental results and the Sternling and Scriven criteria of stability. In this paper, the analysis is further extended to include oscillatory instability, which was neglected in the previous analysis. The results show that oscillatory instability takes an important role in the onset of instabilities, and also that oscillatory instability always takes place when the destabilizing Rayleigh effect and the stabilizing Marangoni effect are competing. It is suggested that the oscillatory instability of this kind may be correlated to the onset of violent interfacial turbulence or eruption.

5 citations


01 Sep 1980

5 citations


Journal ArticleDOI
TL;DR: In this paper, a relatively unknown type of instability induced by high intensity interphase mass transfer was found to occur during the absorption of highly soluble gases and should be considered in conjunction with any associated Marangoni phenomena.

4 citations


Journal ArticleDOI
TL;DR: In this paper, the mass transfer resistances of the diffusive transfers to and from the interface with the interfacial resistance were measured by means of modified liquid scintillation techniques to within 0.66 μm of the interface and in the bulk of the organic phase (toluene) during the solute transfer from the organic to water phase in a horizontal cylindrical flow channel with concurrent flow of the phases at different temperatures, flow rates and solute concentrations.

Journal ArticleDOI
TL;DR: In this paper, a linear perturbation method was employed to determine the condition for neutral stability in spherical liquid shells induced by surface tension mechanism, and three possible boundary conditions were considered: at least one boundary free or both.


Journal ArticleDOI
TL;DR: In this article, the rates of evaporation of alloying elements from Fe-Cu, Fe-Sn and Fe-Cr melts under vacuum have been investigated by using an experimental apparatus which was made up of a Langmuir's Evaporation cell and of target plates for collecting evaporated material.
Abstract: The rates of evaporation of alloying elements from Fe-Cu, Fe-Sn and Fe-Cr melts under vacuum have been investigated by using an experimental apparatus which was made up of a Langmuir's evaporation cell and of target plates for collecting evaporated material. These melts were so heated as to change stirring conditions by resistance heating or by high frequency induction.The evaporation rates are of first order with respect to all the alloying elements. The evaporation from Fe-Sn systems is mainly controlled by the evaporation step on the surface. However, in the cases of Fe-Cu and Fe-Cr systems, both the evaporation step and the diffusion step through the liquid boundary layer are rate controlling, i.e. in these systems the total evaporation process is of mixed control.When tin which is a surface active element evaporated from the specimen, surface movement due to surface pressure (Marangoni effect) is observed, and the mass transfer is increased. Resume La vitesse d'evaporation des elements d'alli...

Journal ArticleDOI
TL;DR: In this paper, the authors measured volumetric flow rates in Marangoni films of liquid natural gas and compared them with the maximum possible flow rates for the whole film, but detailed comparison is hindered by an incomplete knowledge of the physical properties of the liquid in the films.