Auflistung nach Autor "Karapetsas, G."
Anzeige der Dokumente 1-13 von 13
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Bubble rise dynamics in a viscoplastic material
(2015)The axisymmetric dynamics of a bubble rising in a Bingham fluid under the action of buoyancy is studied. The Volume-of-Fluid (VOF) method is used to solve the equations of mass and momentum conservation, coupled to an ... -
Effect of Contact Line Dynamics on the Thermocapillary Motion of a Droplet on an Inclined Plate
(2013)We study the two-dimensional dynamics of a droplet on an inclined, nonisothermal solid substrate. We use lubrication theory to obtain a single evolution equation for the interface, which accounts for gravity, capillarity, ... -
The Free (Open) Boundary Condition at inflow boundaries
(2012)The Free (or Open) Boundary Condition (FBC, OBC) was proposed by Papanastasiou et al. (A new outflow boundary condition, Int. J. Numer. Meth. Fluids 14 (1992) 587-608) to handle truncated domains with synthetic boundaries ... -
Linear and nonlinear stability of hydrothermal waves in planar liquid layers driven by thermocapillarity
(2013)A shallow planar layer of liquid bounded from above by gas is set into motion via the thermocapillary effect resulting from a thermal gradient applied along its interface. Depending on the physical properties of the liquid ... -
Non-isothermal bubble rise: non-monotonic dependence of surface tension on temperature
(2015)We study the motion of a bubble driven by buoyancy and thermocapillarity in a tube with a non-uniformly heated walls, containing a so-called 'self-rewetting fluid'; the surface tension of the latter exhibits a parabolic ... -
Non-linear dynamics of a viscoelastic film subjected to a spatially periodic electric field
(2015)We investigate the non-linear dynamics of the electrohydrodynamic instability of a viscoelastic polymeric film under a patterned mask. We develop a computational model and carry out 2D numerical simulations fully accounting ... -
Numerical simulation of pressure-driven displacement of a viscoplastic material by a Newtonian fluid using the lattice Boltzmann method
(2015)The pressure-driven displacement of a non-Newtonian fluid by a Newtonian fluid in a two-dimensional channel is investigated via a multiphase lattice Boltzmann method using a non-ideal gas equation of state well-suited for ... -
On phase change in Marangoni-driven flows and its effects on the hydrothermal-wave instabilities
(2014)This paper investigates the effects of phase change on the stability of a laterally heated liquid layer for the first time. The interface is open to the atmosphere and vapor diffusion is the rate-limiting mechanism for ... -
On the stick-slip flow from slit and cylindrical dies of a Phan-Thien and Tanner fluid model. II. Linear stability analysis
(2013)During extrusion of viscoelastic fluids various flow instabilities may arise resulting in a distorted free surface. In order to investigate the factors generating these instabilities we performed a linear stability analysis ... -
The primary instability of falling films in the presence of soluble surfactants
(2013)We investigate the linear stability of a film flowing down a solid substrate in the presence of soluble surfactants. The Navier-Stokes equations for the liquid motion are considered, together with advection-diffusion ... -
The role of surfactants on the mechanism of the long-wave instability in liquid film flows
(2014)The analysis for the physical mechanism of the long-wave instability in liquid film flow is extended to take into account the presence of a surfactant of arbitrary solubility. The Navier-Stokes equations are supplemented ... -
Some experiences with the slip boundary condition in viscous and viscoelastic flows
(2013)A slip boundary condition (SBC) has been known to occur at solid boundaries in a variety of materials processing including polymer processing. In the present work, implementation of the SBC has been tested for viscous and ... -
Thermocapillary-Driven Motion of a Sessile Drop: Effect of Non-Monotonic Dependence of Surface Tension on Temperature
(2014)We study the thermocapillary-driven spreading of a droplet on a nonuniformly heated substrate for fluids associated with a non-monotonic dependence of the surface tension on temperature. We use lubrication theory to derive ...