1. On the Pressure Cavities in Topaz, Beryl, and Diamond, and their bearing on Geological Theories

1862 ◽  
Vol 4 ◽  
pp. 548-549
Author(s):  
David Brewster
Keyword(s):  
Immiscible Fluids ◽  
Two Fluids ◽  
Primitive Forms

In this paper the author gave a brief account of the various phenomena of fluid and gaseous cavities which he had discovered in diamond, topaz, beryl, and other minerals. He described—1. Cavities with two immiscible fluids, the most expansible of which has received the name of Brewstolyne, and the most dense that of Cryptolyne, from the American and French mineralogists.2. Cavities containing only one of these fluids.3. Cavities containing the two fluids, and also crystals of various primitive forms, some of which melt by heat and recrystallise in cooling.4. Cavities containing gas and vapour.

Fabrication of Plastic Micro-Channels for Microfluidics Solvent Extraction

2015 ◽  
Author(s):  
Tatjana Dankovic ◽  
Gareth Hatch ◽  
Alan Feinerman
Keyword(s):  
Solvent Extraction ◽  
Close Contact ◽  
Middle Layer ◽  
Extraction Process ◽  
Immiscible Fluids ◽  
Immiscible Fluid ◽  
Intimate Contact ◽  
Two Fluids ◽  
Massively Parallel Systems ◽  
Micro Channels

In this work plastic micro channel systems were investigated as a potential device for micro solvent extraction of rare earth elements. The proposed microfluidic structures are made by laser welding of three layers of inexpensive thermoplastic films which form separate paths (top and bottom channels) for each of the immiscible fluids. The middle layer is perforated in order to provide contact between two fluids and to enable the extraction process. Experiments were performed to show that two different immiscible fluids (water and 1-octanol) can flow through the fabricated device and exit at separate outlets without mixing even when those fluids get into close contact within the main channel. Experimental results for single devices show that immiscible fluids can be brought into intimate contact and then separated with compliant polymeric microfluidic devices. The transfer of a compound from one immiscible fluid to the other was verified by dye exchange between the immiscible fluids. The same fabrication method is a promising technique for fabrication of massively parallel systems with larger throughput.

Lattice Boltzmann Simulation of Surface Tension Dominated Vortices Behaviour in Two-Phase Mixing Layer

2006 ◽  
Author(s):  
Y. Y. Yan ◽  
Y. Q. Zu
Keyword(s):  
Surface Tension ◽  
Multiphase Flow ◽  
Lattice Boltzmann ◽  
Mixing Layer ◽  
Vertical Direction ◽  
Immiscible Fluids ◽  
Interfacial Interactions ◽  
Two Phase ◽  
Phase Mixing ◽  
Two Fluids

Surface tension dominating mixings and interfacial interactions are major phenomena of multiphase flow in microchannels and a variety of micro mixers. Such phenomena are concerned with interfacial interactions not only at fluid-solid interface but also at different fluids/phases interfaces. In this paper, vortices behaviours in a mixing layer of two immiscible fluids are studied numerically. The lattice Boltzmann method (LBM) is employed to simulat surface tension dominated mixing process. As a mesoscopic numerical method, the LBM has many advantages, which include the ability of incorporating microscopic interactions, the simplicity of programming and the nature of parallel algorithm and is therefore ideal for simulating multiphase flow. In this article, the index function methodology of the LBM is employed to simulate surface tension dominated vertices behaviour in a two-dimensional immiscible two-phase mixing layer. The initial interface between two-fluids is evenly distributed around the midpoint in vertical direction. Different velocity perturbations which consist of a basic wave and a series of sub-harmonic waves are forced at the entrance of a rectangular mixing layer of the flow field. By changing the strength of surface tension and the combinations of perturbation waves, the effects of the surface tension and the velocity perturbation on vortices merging are investigated. The vortices contours and frequency spectrums are used to analyse the mechanism of vortices merging. Some interesting phenomena, which do not take place in a single-phase mixing layer, are observed and the corresponding mechanism is discussed in details.

Starting Poiseuille Flow in a Circular Tube With Two Immiscible Fluids

2018 ◽  
Vol 141 (3) ◽  
Author(s):  
Chiu-On Ng ◽  
C. Y. Wang
Keyword(s):  
Circular Tube ◽  
Slip Length ◽  
Finite Thickness ◽  
Applied Pressure ◽  
Immiscible Fluids ◽  
Circular Duct ◽  
Two Fluids ◽  
Plasma Skimming ◽  
Start Up ◽  
Starting Flow

Starting flow due to a suddenly applied pressure gradient in a circular tube containing two immiscible fluids is solved using eigenfunction expansions. The orthogonality of the eigenfunctions is developed for the first time for circular composite regions. The problem, which is pertinent to flow lubricated by a less viscous near-wall fluid, depends on the ratio of the radius of the core region to that of the tube, and the ratios of dynamic and kinematic viscosities of the two fluids. In general, a higher lubricating effect will lead to a longer time for the starting transient to die out. The time development of velocity profile and slip length are examined for the starting flows of whole blood enveloped by plasma and water enveloped by air in a circular duct. Owing to a sharp contrast in viscosity, the starting transient duration for water/air flow can be ten times longer than that of blood/plasma flow. Also, the slip length exhibits a singularity in the course of the start-up. For blood with a thin plasma skimming layer, the singularity occurs very early, and hence for the most part of the start-up, the slip length is nearly a constant. For water lubricated by air of finite thickness, the singularity may occur at a time that is comparable to the transient duration of the start-up, and hence, an unsteady slip length has to be considered in this case.

RIEMANN SOLUTIONS FOR VERTICAL FLOW OF THREE PHASES IN POROUS MEDIA: SIMPLE CASES

2013 ◽  
Vol 10 (02) ◽  
pp. 335-370 ◽  
Author(s):  
PANTERS RODRÍGUEZ-BERMÚDEZ ◽  
DAN MARCHESIN
Keyword(s):  
Conservation Laws ◽  
Spatial Dimension ◽  
Immiscible Fluids ◽  
Fractional Flow ◽  
Two Phase ◽  
Riemann Solutions ◽  
Two Fluids ◽  
Three Phase ◽  
Three Phase Flow ◽  
Curve Method

We study Riemann solutions for a system of two nonlinear conservation laws that models buoyancy-driven flow of three immiscible fluids in a porous medium, which do not exchange mass. We also assume that the fluids are incompressible and the flow occurs in the vertical spatial dimension. We consider the simplified case in which two of the three fluids have equal densities, obtaining the Riemann solutions by the wave curve method. As expected, the solutions contain waves traveling both upwards and downwards. The sequences of waves contain rarefactions, shocks (sometimes traveling with characteristic speed), and constant states. The shocks found in this work are proper or generalized Lax shock waves. The solutions we found are L1-continuous with respect to the initial data. Waves involving only two fluids often take part in three-phase flow Riemann solutions; this is the basis of a useful tool (the wedge construction) to obtain shocks separating states in distinct two-phase regimes having a common fluid. This tool is similar to fractional flow theory, or Oleinik's convex construction. In this investigation, the wave curve method from the theory of conservation laws is combined with numerical calculations.

Couette flow of two fluids between concentric cylinders

1985 ◽  
Vol 150 ◽  
pp. 381-394 ◽  
Author(s):  
Yuriko Renardy ◽  
Daniel D. Joseph
Keyword(s):  
Surface Tension ◽  
Viscous Fluid ◽  
Thin Layer ◽  
Couette Flow ◽  
Numerical Study ◽  
Outer Cylinder ◽  
Immiscible Fluids ◽  
Stable Configuration ◽  
Two Fluids ◽  
Concentric Cylinders

We consider the flow of two immiscible fluids lying between concentric cylinders when the outer cylinder is fixed and the inner one rotates. The interface is assumed to be concentric with the cylinders, and gravitational effects are neglected. We present a numerical study of the effect of different viscosities, different densities and surface tension on the linear stability of the Couette flow. Our results indicate that, with surface tension, a thin layer of the less-viscous fluid next to either cylinder is linearly stable and that it is possible to have stability with the less dense fluid lying outside. The stable configuration with the less-viscous fluid next to the inner cylinder is more stable than the one with the less-viscous fluid next to the outer cylinder. The onset of Taylor instability for one-fluid flow may be delayed by the addition of a thin layer of less-viscous fluid on the inner wall and promoted by a thin layer of more-viscous fluid on the inner wall.

Interactive Evolution of a Bicontinuous Structure

Leonardo ◽  
2020 ◽  
Vol 53 (3) ◽  
pp. 327-330 ◽  
Author(s):  
Florian Stenger ◽  
Axel Voigt
Keyword(s):  
Possible Worlds ◽  
Time Frame ◽  
Immiscible Fluids ◽  
Fluid Interface ◽  
Interface Area ◽  
Time Step ◽  
Two Fluids ◽  
Bicontinuous Structure ◽  
Interactive Experience ◽  
Intuitive Manner

The authors describe an installation that was shown at the exhibition The Best of All Possible Worlds at Technische Sammlungen Dresden in 2016. The installation provided an interactive experience of the evolution of a complex bicontinuous structure of two immiscible fluids. The evolution is driven by the surface tension of the interface of the two fluids, which results in a continuous reduction of the interface area. The process is mathematically described by a partial differential equation, which is numerically solved. In each time step, the structure, visualized by the fluid-fluid interface, is rendered and shown on an elastic display. According to the deformation of the display, the corresponding time frame is projected. By pushing against the elastic display, one therefore can interact with the structure and evolve it in time in a playful and intuitive manner.

Revisiting the linear stability analysis and absolute–convective transition of two fluid core annular flow

2019 ◽  
Vol 865 ◽  
pp. 743-761 ◽  
Author(s):  
D. Salin ◽  
L. Talon
Keyword(s):  
Linear Stability ◽  
Explicit Solution ◽  
Cylindrical Tube ◽  
Flow Equation ◽  
Immiscible Fluids ◽  
Creeping Flow ◽  
Complex Eigenvalue ◽  
Miscible Fluids ◽  
Two Fluids ◽  
Fluid Core

Numerous experimental, numerical and theoretical studies have shown that core annular flows can be unstable. This instability can be convective or absolute in different situations: miscible fluids with matched density but different viscosities, creeping flow of two immiscible fluids or buoyant flow along a fibre. The analysis of the linear stability of the flow equation of two fluids injected in a co-current and concentric manner into a cylindrical tube leads to a rather complex eigenvalue problem. Until now, all analytical solution to this problem has involved strong assumptions (e.g. lack of inertia) or approximations (e.g. developments at long or short wavelengths) even for axisymmetric disturbances. However, in this latter case, following C. Pekeris, who obtained, almost seventy years ago, an elegant explicit solution for the dispersion relationship of the flow of a single fluid, we derive an explicit solution for the more general case of two immiscible fluids of different viscosity, density and inertia separated by a straight interface. This formulation is well adapted to commercial software. First, we review the creeping flow limit (zero Reynolds number) of two immiscible fluids as it is used in microfluidics. Secondly, we consider the case of two fluids of different viscosities but of the same density in the absence of surface tension and also without diffusion (i.e. miscible fluids with infinite Schmidt number). In both cases, we study the transition from convective to absolute instability according to the different control parameters.

scholarly journals Driven particles at fluid interfaces acting as capillary dipoles

2015 ◽  
Vol 770 ◽  
pp. 5-26 ◽  
Author(s):  
Aaron Dörr ◽  
Steffen Hardt
Keyword(s):  
Azimuthal Angle ◽  
Interaction Force ◽  
Dipolar Interaction ◽  
Immiscible Fluids ◽  
Spherical Particles ◽  
Fluid Interfaces ◽  
Linear Superposition ◽  
Two Fluids ◽  
Particle Velocities ◽  
Superposition Approximation

The dynamics of spherical particles driven along an interface between two immiscible fluids is investigated asymptotically. Under the assumptions of a pinned three-phase contact line (TCL) and very different viscosities of the two fluids, a particle assumes a tilted orientation. As it moves, it causes a deformation of the fluid interface which is also computed. The case of two interacting driven particles is studied via the linear superposition approximation. It is shown that the capillary interaction force resulting from the particle motion is dipolar in terms of the azimuthal angle and decays with the fifth power of the inter-particle separation, similar to a capillary quadrupole originating from undulations of the TCL. The dipolar interaction is demonstrated to exceed the quadrupolar interaction at moderate particle velocities.

scholarly journals Mixed Convection in Lid-Driven “T” Shallow Cavity Heated From Bottom and Filled by Two Immiscible Fluids of Air and Al2O3-Water Nanofluid

2020 ◽  
Vol 330 ◽  
pp. 01008
Author(s):  
Aimad koulali ◽  
Bachir Meziani ◽  
Djamel Sadaoui ◽  
Massinissa Adnani ◽  
Adel Sahi
Keyword(s):  
Mixed Convection ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Thermal Characteristics ◽  
Immiscible Fluids ◽  
Geometrical Shape ◽  
Particle Volume ◽  
Convex Shape ◽  
Two Fluids ◽  
Shallow Cavity

This work present numerical simulation results of mixed convection in lid-driven “T” shallow cavity, filled by two immiscible fluids layers of air and Al2O3-water nanofluid. Mixed convection condition is created by the upper wall movement and temperature difference between the alveolus bottom and upper wall. Hydrodynamic and thermal characteristics of the flow have been predicted by solving the Navier- Stokes and energy equation using finite volume method. Coupling between two fluids layers are achieved using continuity of temperature and velocity at the interface air-nanofluid. Nano-particle volume fraction effect and geometrical shape of alveolus sidewalls (plane shape, concave shape and convex shape) have been chosen as discussed parameters. Analysis of obtained results shows that the heat transfer rate decreased with increasing volume fraction of solid inside the nanofluid layer. In addition, geometrical shape of alveolus sidewalls has a poor effect on flow structure and isotherms distribution in the physical domain.

scholarly journals Convective Heat and Mass Transfer of Two Fluids in a Vertical Channel

2020 ◽  
Author(s):  
Suresh Babu Baluguri ◽  
G. Srinivas
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Mathematical Model ◽  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Convective Heat ◽  
Vertical Channel ◽  
Immiscible Fluids ◽  
Boundary Layer Equations ◽  
Two Fluids

A mathematical model for convective heat and mass transfer of two immiscible fluids in a vertical channel of variable width with thermo-diffusion, diffusion-thermal effects is presented. The governing boundary layer equations generated for momentum, angular momentum, energy and species concentration are solved with appropriate boundary conditions using Galeriken finite element method. The effects of the pertinent parameters are studied in detail. Furthermore, the rate of heat transfer, mass transfer and shear stress near both walls is analyzed.

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