83 research outputs found
Coarse-grained description of thermo-capillary flow
A mesoscopic or coarse-grained approach is presented to study
thermo-capillary induced flows. An order parameter representation of a
two-phase binary fluid is used in which the interfacial region separating the
phases naturally occupies a transition zone of small width. The order parameter
satisfies the Cahn-Hilliard equation with advective transport. A modified
Navier-Stokes equation that incorporates an explicit coupling to the order
parameter field governs fluid flow. It reduces, in the limit of an infinitely
thin interface, to the Navier-Stokes equation within the bulk phases and to two
interfacial forces: a normal capillary force proportional to the surface
tension and the mean curvature of the surface, and a tangential force
proportional to the tangential derivative of the surface tension. The method is
illustrated in two cases: thermo-capillary migration of drops and phase
separation via spinodal decomposition, both in an externally imposed
temperature gradient.Comment: To appear in Phys. Fluids. Also at
http://www.scri.fsu.edu/~vinals/dj1.p
Non-equilibrium interface equations: An application to thermo-capillary motion in binary systems
Interface equations are derived for both binary diffusive and binary fluid
systems subjected to non-equilibrium conditions, starting from the
coarse-grained (mesoscopic) models. The equations are used to describe
thermo-capillary motion of a droplet in both purely diffusive and fluid cases,
and the results are compared with numerical simulations. A mesoscopic chemical
potential shift, owing to the temperature gradient, and associated mesoscopic
corrections involved in droplet motion are elucidated.Comment: 12 pages; Latex, revtex, ap
A coarse grained approach to thermocapillarity effects in binary systems
An coarse-grained approach to thermocapillarity effects in binary fluid systems is discussed along with example numerical results
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