Journal ArticleDOI
Interfacial turbulence: Hydrodynamic instability and the marangoni effect
C.V. Sternling,L. E. Scriven +1 more
TLDR
In this article, a simplified mathematical model has been analyzed in order to detail the mechanism of the "interfacial engine" which supplies the mechanical energy of interfacial turbulence, which is a manifestation of hydrodynamic instability, touched off by ever present, small, random fluctuations about the interface.Abstract:
The origin of interfacial turbulence, spontaneous agitation of the interface between two unequilibrated liquids, has been explained in terms of classical flow, diffusion, and surface processes. The essence of the explanation is the long-known though much neglected Marangoni effect, wherein movement in an interface is caused by longitudinal variations of interfacial tension. It is proposed that interfacial turbulence is a manifestation of hydrodynamic instability, which is touched off by ever present, small, random fluctuations about the interface.
A simplified mathematical model has been analyzed in order to detail the mechanism of the “interfacial engine” which supplies the mechanical energy of interfacial turbulence. In its present form the analysis incorporates several drastic simplifications, though ways of removing some of these have been suggested. The groundwork has been laid for the more elaborate analyses that are needed for a decisive test of the theory.
The analysis shows how some systems may be stable with solute transfer in one direction yet unstable with transfer in the opposite direction, a striking result. It also suggests that interfacial turbulence is usually promoted by (1) solute transfer out of the phase of higher viscosity, (2) solute transfer out of the phase in which its diffusivity is lower, (3) large differences in kinematic viscosity and solute diffusivity between the two phases, (4) steep concentration gradients near the interface, (5) interfacial tension highly sensitive to solute concentration, (6) low viscosities and diffusivities in both phases, (7) absence of surface-active agents, and (8) interfaces of large extent.
That some of these effects have been observed in the laboratory lends credence to the theory.read more
Citations
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Journal ArticleDOI
Underdamped capillary wave caused by solutal Marangoni convection in immiscible liquids
Fei Wang,Fei Wang,Marouen Ben Said,Marouen Ben Said,Michael Selzer,Michael Selzer,Britta Nestler,Britta Nestler +7 more
TL;DR: In this paper, the authors used a Cahn-Hilliard-Navier-Stokes model with a capillary tensor to account for solutal Marangoni force and observed an interfacial wave at the interface of two immiscible liquids.
Journal ArticleDOI
Surface viscosity in simple liquids.
TL;DR: In this article , the collective dynamics of interfacial layers in molecular simulations of simple liquids are used to estimate the surface viscosity of these simple liquids, which is 8-16 times smaller than that of the bulk fluid at the thermodynamic point considered.
Journal ArticleDOI
Crystal growth in two-layer fluid systems in microgravity
TL;DR: A numerical study of the crystal growth in zero gravity with the use of an additional liquid layer for the ampoule-free variant of zone melting (floating-zone method) has been conducted as discussed by the authors.
Convective amplitudes of Rayleigh-Benard-Marangoni cellular convection with transient gas-liquid mass transfer
Muthasim Fahmy,Zhifa Sun +1 more
TL;DR: In this paper, a stochastic Ginzburg-Landau equations under Rayleigh-Benard-Marangoni convection have been developed from the soluto-hydrodynamics of a gas-liquid solute transfer system with a transient penetration type base concentration profile.
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