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.

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.

scholarly journals Numerical Analysis of Unsteady Laminar Flow past a Pentagonal Obstacle

2021 ◽  
Vol 10 (2) ◽  
pp. 968-974
Keyword(s):  
Laminar Flow ◽  
Flow Direction ◽  
Rectangular Channel ◽  
Time Frame ◽  
Two Dimensional ◽  
Fluid Inertia ◽  
Time Step ◽  
The Face ◽  
Computational Fluid Dynamics Cfd ◽  
Current Article

The current article dispenses the numerical investigation of a two dimensional unsteady laminar flow of incompressible fluid passing a regular pentagonal obstacle in an open rectangular channel. The centre of attention of this work is the comparison of drag coefficients estimated for two distinct cases based on the orientation of face and corner of an obstacle against the flow direction. The numerical results shows that the corner – oriented obstacle bring about 42% larger value of drag coefficient at Re = 500 than face – oriented obstacle. The substantial growth in the expanse of vortex behind obstacle (presented as a function of fluid inertia 25 < Re < 500) is analyzed through the contours and streamline patterns of velocity field. The two eddies in the downstream become entirely unsymmetrical at Re = 500 for both the cases, whereas; the flow separation phenomena occurs a bit earlier in the face – oriented case at Re = 250. Two dimensional Pressure – Based – Segregated solver is employed to model the governing equations written in velocity and pressure fields. The numerical simulations of unsteady flow are presented for 50 seconds time frame with time step 0.01 by using one of the best available commercial based Computational Fluid Dynamics (CFD) software, ANSYS 15.0.

A moving fluid interface. Part 2. The removal of the force singularity by a slip flow

1977 ◽  
Vol 79 (2) ◽  
pp. 209-229 ◽  
Author(s):  
L. M. Hocking
Keyword(s):  
Contact Line ◽  
Slip Flow ◽  
Slip Condition ◽  
Solid Boundary ◽  
Parallel Plates ◽  
Fluid Interface ◽  
Slip Coefficient ◽  
Outer Flow ◽  
Normal Contact ◽  
Two Fluids

If the no-slip condition is used to determine the flow produced when a fluid interface moves along a solid boundary, a non-integrable stress is obtained. In part 1 of this study (Hocking 1976), it was argued that, when allowance was made for the presence of irregularities on the solid boundary, an effective slip coefficient could be found, which might remove the difficulty.This paper examines the effect of a slip coefficient on the flow in the neighbourhood of the contact line. Particular cases which are solved in detail are liquid–gas interfaces at an arbitrary angle, and normal contact of fluids of arbitrary viscosity. The contribution of the vicinity of the contact line to the force on the boundary is obtained.The inner region, near the contact line, must be matched with an outer flow, in which the no-slip condition can be applied, in order to obtain the total value of the force on the boundary. This force is determined for the flow of two fluids between parallel plates and in a pipe, with a plane interface. The enhanced resistance produced by the presence of the interface is calculated, and it is shown to be equivalent to an increase in the length of the column of fluid by a small multiple of the pipe radius.

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.

scholarly journals A THEORETICAL STUDY OF OSCILLATIONS OF TWO IMMISCIBLE FLUIDS IN A LIMITED TANK

2021 ◽  
pp. 97-113
Author(s):  
Ko Ko Win ◽  
◽  
A.N. Temnov ◽  
Keyword(s):  
Differential Equations ◽  
Nonlinear Oscillations ◽  
Nonlinear Differential Equations ◽  
Nonlinear Effects ◽  
Immiscible Fluids ◽  
Forced Oscillations ◽  
Fluid Interface ◽  
Response Characteristics ◽  
Taylor Series Expansions ◽  
Instability Regions

In the paper, the nonlinear oscillations of a two-layer fluid that completely fills a limited tank are theoretically studied. To determine any smooth function on the deflected interface, the Taylor series expansions are considered using the values of the function and its normal derivatives on the undisturbed interface of the fluids. Using two fundamental asymmetric harmonics, which are generated in two mutually perpendicular planes, the differential equations of nonlinear oscillations of the two-layer fluid interface are investigated. As a result, the frequency-response characteristics are presented and the instability regions of the forced oscillations of the two-layer fluid in the cylindrical tank are plotted, as well as the parametric resonance regions for different densities of the upper and lower fluids. The Bubnov-Galerkin method is used to plot instability regions for the approximate solution to nonlinear differential equations. At the final stage of the work, the nonlinear effects resulting from the interaction of fluids with a rigid tank that executes harmonic oscillations at the interface of the fluids are theoretically studied.

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.

Experimental Investigation on Additively Manufactured Transpiration and Film Cooling Structures

2018 ◽  
Author(s):  
Zheng Min ◽  
Gan Huang ◽  
Sarwesh Narayan Parbat ◽  
Li Yang ◽  
Minking K. Chyu
Keyword(s):  
Additive Manufacturing ◽  
Blood Vessel ◽  
Film Cooling ◽  
Area Ratio ◽  
Manufacturing Technology ◽  
Transpiration Cooling ◽  
Fluid Interface ◽  
Interface Area ◽  
Cooling Effectiveness ◽  
Additive Manufacturing Technology

The last 50 years has witnessed significant improvement in film cooling technologies while transpiration cooling is still not implemented in turbine airfoil cooling. Although transpiration cooling could provide higher cooling efficiency with less coolant consumption compared to film cooling, the fine pore structure and high porosity in transpiration cooling metal media always raised difficulties in conventional manufacturing. Recently, the rapid development of additive manufacturing has provided a new perspective to address such challenge. With the capability of the innovative powder bed selective laser metal sintering (SLMS) additive manufacturing technology, the complex geometries of transpiration cooling part could be precisely fabricated and endued with improved mechanical strength. Present study utilized the SLMS additive manufacturing technology to fabricate the transpiration cooling and film cooling structures with Inconel 718 supperalloy. Five different types of porous media including two perforated plates with different hole pitches, metal sphere packing, metal wire mesh and blood vessel shaped passages for transpiration cooling were fabricated by EOS M290 System. One laidback fan-shaped film cooling coupon was also fabricated with the same printing process as the control group. Heat transfer tests under 3 different coolant mass flow rates and 4 different mainstream temperatures were conducted to evaluate the cooling performance of the printed coupons. The effects of geometry parameters including porosity, surface outlet area ratio and internal solid-fluid interface area ratio were investigated as well. The results showed that the transpiration cooling structures generally had higher cooling effectiveness than film cooling structure. The overall average cooling effectiveness of blood vessel shaped transpiration cooling reached 0.35, 0.5 and 0.57 respectively with low (1.2%), medium (2.4%) and high (3.6%) coolant injection ratios. The morphological parameters analysis showed the major factor that affected the cooling effectiveness most was the internal solid-fluid interface area ratio for transpiration cooling. This study showed that additive manufactured transpiration cooling could be a promising alternative method for turbine blade cooling and worthwhile for further investigations.

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.

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