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Displaying 6811-6820 on page 682 of 7662. Per Page  
  • Determination of Non-Equilibrium Surface Tension Gradients in Marangoni Thermal Flows: Application to Aqueous Solutions of Fatty Alcohols
  • Abstract This study illustrates a relevant and practical method to determine the effective surface tension gradient in a layer subjected to a lateral temperature difference. In general, this can be hardly performed in situ without perturbing the flow. For this reason we rely on an indirect determination approach. A simple model is developed that relates the surface tension gradient to other quantities that can be measured without introducing significant disturbances in the system. Measurements of these quantities are performed in a set-up where the flow corresponds with a good approximation to a one-dimensional model. A previously used set-up has been upgraded…
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  • Simulation of Sloshing with the Volume of Fluid Method
  • Abstract This paper opens a new horizon on the simulation of sloshing phenomena. One of the most popular Finite Volume methods called VOF (Volume Of Fluid) method is used for tracking the flow in containers. The algorithm is tested for different fluid elevations, physical conditions in different road curves and liquid properties. The method is then validated against an analytical and another numerical solution. These comparisons show that the VOF can effectively solve the sloshing problem for different fluids and a variety of physical and geometrical conditions.
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  • The Influence of Flow Pressure Gradient on Interfacial Wave Properties in Annular Two-Phase Flow at Microgravity and Normal Gravity Conditions
  • Abstract Data on air-water co-current two-phase annular flow in a tube with an inner diameter of 9.525 mm (3/8 in) were previously collected at both microgravity u-g and normal gravity (1-g) conditions. The data contained measurements of pressure drop, in addition to previously published data of liquid film thickness. This paper presents the results and analysis of the influence of flow pressure gradient on interfacial wave properties of annular flow at both microgravity and normal gravity. The examined wave properties include wave base thickness, wave height (or roughness height), wave spacing, wave speed and wave frequency. It was found that, the…
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  • Permeability and Thermodiffusion Effect in a Porous Cavity Filled with Hydrocarbon Fluid Mixtures
  • Abstract This paper numerically investigates the interaction between thermodiffuion and buoyancy driven convection in a laterally heated vertical porous cavity for different permeability. The Firoozabadi model is applied to binary hydrocarbon mixtures: (i) the mixture of 1,2,3,4 tetrahydronaphtalene (THN) and dodecane (C12) with mass fraction of 50% for each component, (ii) 1,2,3,4 tetrahydronaphtalene and isobutylbenzene (IBB) with mass fraction of 50% for each component, and (iii) isobutylbenzene and dodecane with mass fraction of 50% for each component. The thermal and molecular diffusion coefficients, which are functions of the temperature and other properties of mixture, are calculated at each point of the…
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  • Modeling of Dendritic Growth in Alloy Solidification with Melt Convection
  • Abstract In typical solidification processes the flow of molten metal is usually regarded as an unavoidable phenomenon potentially affecting the morphology of dendritic growth. Fundamental understanding of such flow is thus important for predicting and controlling solidification microstructures. This paper presents numerical simulations on the evolution of dendritic microstructures with melt convection. A two-dimensional modified cellular automaton (MCA) coupled with a transport model is developed to simulate solidification of binary and ternary alloys in the presence of fluid flow. This model takes into account the effects of the constitutional undercooling and curvature undercooling on the equilibrium interface temperature. It also considers…
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  • Molten-Alloy Driven Self-Assembly for Nano and Micro Scale System Integration
  • Abstract Self-assembly is emerging as one of the main methods for construction of heterogeneous systems consisting of multiple component types in nano- and micro-scales. The engineered self-assembly used for system integration involves preparation of parts that can recognize and bind to each other or a template, and perfection of procedures that allow for high yield self-assembly of these parts into a system. Capillary forces resultant from molten alloys are attractive candidates for driving such self-assembly processes as they can simultaneously provide electrical and mechanical connections. The basic self-assembly process is reviewed here. Selection of the appropriate alloy, a critical issue in…
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  • Biological Tissue Growth in a Double-Scaffold Configuration
  • Abstract Numerical simulations and computer-graphics animation can be used as useful tools to discern the physicochemical environmental factors affecting the surface kinetics of growing biological tissues as well as their relative importance in determining growth. A mathematical formalism for such kinetics is proposed through parametric investigation and validated through focused comparison with experimental results. The study relies on the application of a CFD moving boundary (Volume of Fluid) method specially conceived for the simulation of these problems. In the second part of the analysis the case of two samples hydrodynamically interacting in a rotating bioreactor is considered. The interplay between two…
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  • Three-Dimensional Modeling of the Effects of Misalignment on the Growth of Ge1-xSix by The Traveling Solvent Method
  • Abstract A numerical simulation study is carried out for the crystal growth of Ge1-xSixby the Traveling Heater Method (THM). The effects of a geometrical misalignment on the crystal growth are investigated. The full Navier-Stokes equations together with the energy, mass transport and continuity equations are solved numerically using the finite element technique. The application of a misalignment is shown to have a considerable effect on the buoyancy induced flow. An optimal misalignment is determined, that weakens the convective flow, provides a uniform concentration along the growth interface and gives symmetrical characteristics to the three-dimensional buoyancy induced flow.
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  • Electromagnetic Stirring in Crystal Growth Processes
  • Abstract For semiconductor crystal growth from a melt, stirring due to the interaction of a steady electric current and a steady magnetic field can lead to a more uniform distribution of the additives in the crystal. This paper treats the electromagnetic stirring in a cylinder with a weak uniform axial magnetic field and with an electric current between an electrode in the center of the top of the cylinder and an electrode at the vertical wall of the cylinder. The magnitude and distribution of the stirring are studied as functions of the aspect ratio of the cylinder and of the strength…
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Displaying 6811-6820 on page 682 of 7662. Per Page