Walid Hassen¹, Mohamed Naceur Borjini², Habib Ben Aissia¹

FDMP-Fluid Dynamics & Materials Processing, Vol.8, No.4, pp. 381-396, 2012, DOI:10.3970/fdmp.2012.008.381

Abstract In this work we consider the problem related to the electro-thermo-convection of a dielectric fluid in a rectangular enclosure placed between two electrodes. This layer is subjected simultaneously to the injection of electric charges and to a thermal gradient. The influence of the electric Rayleigh number (200 - 1000) on the structure of the flow, the density of electric charge and heat transfer is investigated. An oscillatory flow is observed and discussed in detail. More >

A. A. Nepomnyashchy^1,2, I. B. Simanovskii¹

FDMP-Fluid Dynamics & Materials Processing, Vol.4, No.3, pp. 185-198, 2008, DOI:10.3970/fdmp.2008.004.185

Abstract The development of instabilities under the joint action of the van der Waals forces and Marangoni stresses in a two-layer film on a heated or cooled substrate is considered. It is found that heating from below leads to the acceleration of the decomposition, decrease of the characteristic lateral size of structures, and the increase of the droplets heights. Heating from above leads to slowing down the instability rate and eventually to a complete suppression of the instability. More >

A. Ovcharova¹, N.Stankous²

FDMP-Fluid Dynamics & Materials Processing, Vol.3, No.4, pp. 349-356, 2007, DOI:10.3970/fdmp.2007.003.349

Abstract We consider a deformation of a thin film which is hanging between two solid flat walls under thermal load action. A two-dimensional model is applied to describe the motion of thin layers of viscous nonisothermal liquid under microgravity conditions. The model is based on the Navier-Stokes equations. A numerical analysis of the influence of thermal loads on the deformation and break of freely hanging thin films has been carried out. The mutual influence of capillary and thermo-capillary forces on thin film free surface position has been shown. The results of model problem solutions are presented. More >

A. Laverón-Simavilla¹, V. Lapuerta¹, J. Rodríguez¹, M. A. González¹

FDMP-Fluid Dynamics & Materials Processing, Vol.3, No.4, pp. 339-348, 2007, DOI:10.3970/fdmp.2007.003.339

Abstract A cylindrical liquid bridge supported between two circular-shaped disks in isorotation is considered. The effect of an offset between the rotation axis and the axis of the two supporting disks (eccentricity) on the stability of the liquid bridge is investigated. In a previous work a numerical method used to determine the stability limit for different values of eccentricity was validated comparing these results with analytical and experimental results for small eccentricity values, recovering the same behavior. In this work we use the numerical method to extend the analysis to large values of the eccentricity, finding More >

D.E. Melnikov¹, V.M. Shevtsova²

FDMP-Fluid Dynamics & Materials Processing, Vol.3, No.4, pp. 329-338, 2007, DOI:10.3970/fdmp.2007.003.329

Abstract Thermocapillary convection in a long vertical liquid column (called liquid bridge) subjected to heating from above is considered for a three-dimensional Boussinesq fluid. The problem is solved numerically via finite-volume method. Full system of three dimensional Navier-Stokes equations coupled with the energy equation is solved for an incompressible fluid. Instability sets in through a wave propagating in axial direction with zero azimuthal wave number, which is a unique stable solution over a wide range of supercritical heating. Further increasing the applied temperature difference results in bifurcation of a second wave traveling azimuthally with a slightly More >

U. Schoisswohl¹, H. C. Kuhlmann²

FDMP-Fluid Dynamics & Materials Processing, Vol.3, No.4, pp. 317-328, 2007, DOI:10.3970/fdmp.2007.003.317

Abstract The flow in thermocapillary liquid pools heated or cooled from above can exhibit various flow patterns depending on the thermal conditions and the geometrical constraints. This pattern formation and the respective physical mechanisms are studied numerically by means of a linear-stability analysis. We focus on the transition from the steady axisymmetric to a three-dimensional flow. More >

R. Prud’homme¹, M. El Ganaoui²

FDMP-Fluid Dynamics & Materials Processing, Vol.3, No.2, pp. 161-172, 2007, DOI:10.3970/fdmp.2007.003.161

Abstract Some problems related to solid/liquid phase change are presented. Attention is focused on interface modeling for numerical analysis and one-dimensional directional growing and melting. Microgravity relevance of some situations is emphasized. It is shown, in particular, that in some circumstances melting is not the simple reversal of crystal growth due to some (still poorly known) phenomena (nucleation and growth of liquid droplets in the bulk, solid and liquid dendrites due to a morphological instability of the phase boundary). Relevant mathematical models are discussed and described (to a certain extent) for analysis and/or characterization of these More >

Y. Kamotani¹, S. Matsumoto², S. Yoda²

FDMP-Fluid Dynamics & Materials Processing, Vol.3, No.2, pp. 147-160, 2007, DOI:10.3970/fdmp.2007.003.147

Abstract A Marangoni Convection Modeling Research group was formed in Japan in order to investigate oscillatory thermocapillary flow systematically over a wide range of Prandtl number (Pr). The research by the group represents the current status of the subject. The present article reports the work done by the group members. The work is divided into three Pr ranges (low, medium and high) because the cause of oscillations is different in each range. For the low-Pr case, the transition to oscillatory flow is preceded by a steady bifurcation to three-dimensional convection. For the first time an experimental More >

Evgeny V. Votyakov¹, Egbert A. Zienicke¹

FDMP-Fluid Dynamics & Materials Processing, Vol.3, No.2, pp. 97-114, 2007, DOI:10.3970/fdmp.2007.003.097

Abstract We simulated numerically the laminar flow in the geometry and the magnetic field of the experimental channel used in [Andreev, Kolesnikov, and Thess (2006)]. This provides detailed information about the electric potential distribution for the laminar regime (numerical simulation) and in the turbulent regime as well (experiment). As follows from comparison of simulated and experimental results, the flow under the magnet is determined by the interaction parameter N = Ha² / Re representing the ratio between magnetic force, determined by the Hartmann number Ha, and inertial force, determined by the Reynolds number Re. We compared two variants: (i)(Re,N)=(2000,18.6)… More >

D. E. Melnikov¹, V. M. Shevtsova²

FDMP-Fluid Dynamics & Materials Processing, Vol.1, No.2, pp. 189-200, 2005, DOI:10.3970/fdmp.2005.001.189

Abstract Buoyancy-driven convective flows are numerically analyzed in a cubic enclosure, containing a liquid subjected to a temperature difference between opposite lateral walls; all other walls are thermally insulated. The stationary gravity vector is perpendicular to the applied temperature gradient. The steady flow patterns are investigated within the framework of a liquid particles tracing technique. Three tracing techniques are compared: the first, based on a trilinear interpolation of the liquid velocity defined on the computational grid and an eighth order in time Runge-Kutta method; the second and the third, using a resampling the velocity field on… More >