Y. Okano¹, A. Ishii¹, H. Miyashita¹, H. Minakuchi¹, S. Dost²

FDMP-Fluid Dynamics & Materials Processing, Vol.2, No.4, pp. 261-270, 2006, DOI:10.3970/fdmp.2006.002.261

Abstract The article presents the results of a numerical simulation study that was carried out to examine the effect of g-jitter on the flow and concentration structures observed in the solution of a growth crucible under microgravity conditions. The simulation model considers a simple crucible of electroepitaxy, and assumes crucible rotation and applied axial static magnetic fields to control and minimize the effect of g-jitter induced flow oscillations. More >

V. Pletser¹, R. Bosch², L. Potthast², R. Kassel³

FDMP-Fluid Dynamics & Materials Processing, Vol.2, No.1, pp. 65-76, 2006, DOI:10.3970/fdmp.2006.002.065

Abstract Orbital weightless conditions have been shown to yield better and larger crystals. The Solution Crystallization Diagnostics Facility (SCDF) is a third generation instrument developed by ESA and dedicated to the observation and study with advanced diagnostics nucleation and crystallisation processes of molecules from solutions on board the International Space Station. The SCDF is intended to be used for studies of proteins and large biomolecules, and more generally of any kind of molecules growing from solutions, using the powerful set of diagnostics means available in the SCDF platform. Several protein crystallisation reactors have been developed to study protein and macro-biomolecules assembling… More >

M. Kassemi¹, Y. Wang², S. Barsi^1,3, B.T.F. Chung²

FDMP-Fluid Dynamics & Materials Processing, Vol.2, No.1, pp. 27-46, 2006, DOI:10.3970/fdmp.2006.002.027

Abstract Microgravity experiments, especially materials processing experiments, have often been hampered by presence of unwanted bubbles. In this work, the effect of thermocapillary convection generated by a bubble on the Bridgman growth of a dilute binary alloy in microgravity is investigated numerically. The model is based on the quasi-steady Navier-Stokes equations for the fluid flow in the melt coupled with the conservation equations for transport of energy and species in the growth ampoule. Numerical results indicate three different growth regimes based on the distance between the bubble and the growth interface: a diffusion dominated regime that is separated from a well-mixed… More >

Sayavur I. Bakhtiyarov¹, Dennis A. Siginer²

FDMP-Fluid Dynamics & Materials Processing, Vol.4, No.2, pp. 99-112, 2008, DOI:10.3970/fdmp.2008.004.099

Abstract Levitation of liquid bodies against gravity is a contactless confinement process appropriate for manufacturing very pure materials. A variety of levitation techniques have been developed over the last few decades, such as aerodynamic, acoustic, electrostatic, microwave, and electromagnetic levitations. More recently, a new generation of novel techniques, essentially combinations of the established primary techniques, has been successfully introduced. Examples are acoustic-electric, aerodynamic-acoustic and acoustic-electromagnetic. The purpose of this series of papers in three parts, Bakhtiyarov and Siginer (2007a,b), is to review the advances in electromagnetic levitation (EML) since its introduction as a containerless melting technique, and a tool for the… 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 a change in the bifurcation… More >

Akira Hirata¹

FDMP-Fluid Dynamics & Materials Processing, Vol.3, No.3, pp. 203-230, 2007, DOI:10.3970/fdmp.2007.003.203

Abstract This article is a summary of author's typical research works (over the last four decades) on interphase transport phenomena in the presence of interfacial fluid motion and surface tension gradients on liquid-fluid interfaces, and related applications to single crystal growth and microgravity sciences. A unified theory for momentum, heat and mass transfer on liquid-fluid and solid-fluid interfaces is proposed, which takes into account interface mobility. It is shown that interface contamination and turbulence can be well explained, respectively, by suppression and enhancement of the interfacial velocity induced by surface tension gradients. Transport phenomena on solid spheres, liquid drops and gas… More >

Y. Yan¹, V. Shevtsova², M. Z. Saghir¹

FDMP-Fluid Dynamics & Materials Processing, Vol.1, No.4, pp. 315-328, 2005, DOI:10.3970/fdmp.2005.001.315

Abstract Convection has a major impact on diffusion in fluid mixtures either on the Earth or in the microgravity condition. G-jitters, as the primary source that induces the vibrational convection in space laboratories, should be studied thoroughly in order to improve the diffusion-dominated fluid science experiments. In this paper we consider the effect of g-jitters on thermal diffusion. The mixture water-isopropanol (90:10 wt%) bounded in a cubic cell is simulated with a lateral heating and various vibration conditions. The fluid flow, concentration and temperature distributions are thoroughly analyzed for different g-jitter scenarios. It is shown that the overall effect of vibrations… More >

N.I. Wakayama¹, D.C. Yin², J.W. Qi³

FDMP-Fluid Dynamics & Materials Processing, Vol.1, No.2, pp. 153-170, 2005, DOI:10.3970/fdmp.2005.001.153

Abstract The production of crystals of adequate size and high quality is the "bottleneck'' for three-dimensional structure analysis of protein crystals. In this work, in order to shed additional light on the (still controversial) beneficial effect of microgravity on crystal growth, we focus on recent advanced experimental and theoretical research about the effects of buoyancy-driven convection on protein crystallization. In the light of the numerical studies the following major outcomes can be highlighted: (1) when the crystal size exceeds several dozens of µm, buoyancy-driven convection dominates solute transport near the growing crystal and the crystal growth rate becomes larger than that… More >

Asghar Esmaeeli¹

FDMP-Fluid Dynamics & Materials Processing, Vol.1, No.1, pp. 63-80, 2005, DOI:10.3970/fdmp.2005.001.063

Abstract We use direct numerical simulations to study phase distribution of bubbles under terrestrial and microgravity conditions. The full Navier-Stokes and energy equations, for the flows inside and outside the bubbles, are solved using a front tracking/finite difference technique. Both nearly spherical and deformable bubbles are considered. For buoyancy-driven flows, spherical bubbles at Re = O(10) and deformable ones at Re = O(100) exhibit a uniform spatial distribution at quasi steady-state conditions, while nearly spherical bubbles at Re = O(100) form horizontal rafts. Bubbles, driven by thermocapillary effects in microgravity, also form horizontal rafts, but due to an entirely different mechanism.… More >