scholarly journals Flow regimes during fluid-filled crack propagation in elastic media: Applications to volcanology and magma flow within dykes

2021 ◽  
Author(s):  
Janine Kavanagh ◽  
Thomas Jones ◽  
David Dennis
Keyword(s):  
Laser Sheet ◽  
Fluid Velocity ◽  
Flow Regimes ◽  
Creeping Flow ◽  
Hydroxyethyl Cellulose ◽  
Magma Flow ◽  
System Architectures ◽  
Volcanic Plumbing System ◽  
Penny Shaped Crack ◽  
Fluid Magma

Scaled analogue experiments were conducted to explore the effect of magma flow regimes, characterised by the Reynolds number (Re), on the transit of magma through the lithosphere via fractures. An elastic, transparent gelatine solid (the crust analogue) was injected by a fluid (magma analogue) to create a thin, vertical, and penny-shaped crack that is analogous to a magma-filled crack (dyke). A vertical laser sheet fluoresced passive-tracer particles suspended in the injected fluid, and particle image velocity (PIV) was used to map the location, magnitude, and direction of flow within the growing dyke from its inception to its surface rupture. Experiments were conducted using water, hydroxyethyl cellulose (HEC) or xanthan gum (XG) as the magma analogue. The results suggest that Re has significant impact on the direction of fluid flow within propagating dykes: Re > 0.1 (jet-flow) is characterised by a rapid central rising fluid jet and downflow at the dyke margin, whereas Re < 0.1 (creeping flow) is characterised by broadly uniform velocities across the dyke plane. Re may be underestimated by up to two orders of magnitude if tip velocity rather than internal fluid velocity is used. In nature, these different flow regimes would affect the petrological, geochemical, geophysical, and geodetic measurements of magma movement, key information upon which reconstructions of volcanic plumbing system architectures and their growth are based.

Permeability in the Mushy Zone

2010 ◽  
Vol 649 ◽  
pp. 399-408 ◽  
Author(s):  
R.G. Erdmann ◽  
D.R. Poirier ◽  
A.G. Hendrick
Keyword(s):  
Mushy Zone ◽  
Volume Fraction ◽  
Primary Dendrite ◽  
Fluid Velocity ◽  
Interdendritic Liquid ◽  
Creeping Flow ◽  
Liquid Region ◽  
Local Volume ◽  
Local Volume Fraction ◽  
Deterministic Function

When modeled at macroscopic length scales, the complex dendritic network in the solid-plus-liquid region of a solidifying alloy (the “mushy zone”) has been modeled as a continuum based on the theory of porous media. The most important property of a porous medium is its permeability, which relates the macroscopic pressure gradient to the throughput of fluid flow. Knowledge of the permeability of the mushy zone as a function of the local volume-fraction of liquid and other morphological parameters is thus essential to successfully modeling the flow of interdendritic liquid during alloy solidification. In current continuum models, the permeability of the mushy zone is given as a deterministic function of (1) the local volume fraction of liquid and (2) a characteristic length scale such as the primary dendrite arm spacing or the reciprocal of the specific surface area of the solid-liquid interface. Here we first provide a broad overview of the experimental data, mesoscale numerical flow simulations, and resulting correlations for the deterministic permeability of both equiaxed and columnar mushy zones. A extended view of permeability in mushy zones which includes the stochastic nature of permeability is discussed. This viewpoint is the result of performing extensive numerical simulations of creeping flow through random microstructures. The permeabilities obtained from these simulations are random functions with spatial autocorrelation structures, and variations in the local permeability are shown to have dramatic effects on the flow patterns observed in such microstructures. Specifically, it is found that “lightning-like” patterns emerge in the fluid velocity and that the flows in such geometries are strongly sensitive to small variations in the solid structure. We conclude with a comparison of deterministic and stochastic permeabilities which suggests the importance of incorporating stochastic descriptions of the permeability of the mushy zone in solidification modeling.

PIV and LIF Measurements of Flow in the Vicinity of Moving Interface

2002 ◽  
Author(s):  
Jun Shimizu ◽  
Takahiro Ito ◽  
Yoshiyuki Tsuji ◽  
Yutaka Kukita
Keyword(s):  
Contact Line ◽  
High Speed ◽  
Laser Sheet ◽  
Fluid Velocity ◽  
Argon Laser ◽  
Ccd Camera ◽  
Wall Material ◽  
Video Frame ◽  
Interface Motion ◽  
Stick Slip

The interface between overlaid fluids can become unstable when the fluids are excited vertically. Ito et al. (1999) studied a combined excitation problem where the fluids were excited vertically in a stationary cylinder while the interface motion was restricted by the mobility of the fluid-fluid-wall contact line. They found that the contact line exhibits stick-slip-like motion for the combination of fluids and wall material used in their experiments (water and kerosene oil in a cylinder made of acrylic resin). The flow above and beneath the interface is visualized by adding small particles. A vertical, diametral cross section of the test section is illuminated by a 509-nm Argon laser sheet. The experimental data presented in this paper were taken using ‘EXPANCEL’ particle tracer with a typical diameter of 10 µm, added to the water above and beneath the interface. Pictures are taken by a high-speed CCD camera at a rate of 120 frame/s. Each uninterlaced (120 frame/s) video frame is divided into 640 × 480 pixels for image processing. The fluid velocity is obtained for each 2.95 mm × 2.95 mm area by using the PIV technique. Visualization studies have revealed that the nonuniform velocity distribution above and below the interface extends to a much greater depth than the wave amplitude. Streamlines were taken by using Rhodamine-B fluorescent dye which was added to water beneath the interface and excited with an Ar laser fan beam, with a CCD camera.

scholarly journals Magma flow regimes in sills deduced from Ar isotope systematics of host rocks

2001 ◽  
Vol 106 (B3) ◽  
pp. 4017-4035 ◽  
Author(s):  
Jo-Anne Wartho ◽  
Simon P. Kelley ◽  
Stephen Blake
Keyword(s):  
Flow Regimes ◽  
Magma Flow ◽  
Host Rocks ◽  
Isotope Systematics

scholarly journals Biologically inspired transport of solid spherical nanoparticles in an electrically-conducting viscoelastic fluid with heat transfer

2020 ◽  
Vol 24 (2 Part B) ◽  
pp. 1251-1260 ◽  
Author(s):  
Ahmed Zeeshan ◽  
Mubashir Bhatti ◽  
Nouman Ijaz ◽  
Osman Bég ◽  
Ali Kadir
Keyword(s):  
Heat Transfer ◽  
Relaxation Time ◽  
Hartmann Number ◽  
Volume Fraction ◽  
Fluid Velocity ◽  
Pressure Rise ◽  
Solid Particles ◽  
Creeping Flow ◽  
Axial Pressure Gradient ◽  
Fraction Density

Bio-inspired pumping systems exploit a variety of mechanisms including peristalsis to achieve more efficient propulsion. Non-conducting, uniformly dispersed, spherical nanosized solid particles suspended in viscoelastic medium forms a complex working matrix. Electromagnetic pumping systems often employ complex working fluids. A simulation of combined electromagnetic bio-inspired propulsion is observed in the present article. Currents formation has increasingly more applications in mechanical and medical industry. A mathematical study is conducted for MHD pumping of a bi-phase nanofluid coupled with heat transfer in a planar channel. Two-phase model is employed to separately identity the effects of solid nanoparticles. Base fluid employs Jeffery?s model to address viscoelastic characteristics. The model is simplified using long wavelength and creeping flow approximations. The formulation is taken to wave frame and non-dimensionalise the equations. The resulting boundary value problem is solved analytically, and exact expressions are derived for the fluid velocity, particulate velocity, fluid-particle temperature, fluid and particulate volumetric flow rates, axial pressure gradient and pressure rise. The influence of volume fraction density, Prandtl number, Hartmann number, Eckert number, and relaxation time on flow and thermal characteristics is evaluated in detail. The axial flow is accelerated with increasing relaxation time and greater volume fraction whereas it is decelerated with greater Hartmann number. Both fluid and particulate temperature are increased with increment in Eckert and Prandtl numbers, whereas it is reduced when the volume fraction density increases. With increasing Hartmann number pressure rise is reduced

scholarly journals Finite Element Simulation of the Deformation of a Cell Driven by Creeping Flow

1970 ◽  
Vol 4 ◽  
pp. 29
Author(s):  
F. Serrano Alcalde ◽  
J.M. García-Aznar ◽  
MJ Gómez Benito
Keyword(s):  
Velocity Profile ◽  
Fluid Velocity ◽  
Creeping Flow ◽  
Nucleus Size ◽  
Viscous Forces ◽  
Configuration Change ◽  
Element Simulation ◽  
Variable Section ◽  
A Cell ◽  
Fluid Configuration

The purpose of this work is to calculate the deformation undergone by a cell in function of its nucleus size and mechanical properties. The cell immersed in a fluid go through a variable section channel and it is deformed by fluid forces.Cell deformation into the channel causes changes at the fluid velocity profile. This fluid configuration change results in diferent normal and viscous forces around the cell. Due to strong correlation between cell deformation and fluid velocity profile, a fluidsolid interacción (FSI) is required.

Numerical Investigation of Proppant Transport and Placement Along Opened Bedding Interfaces

2021 ◽  
Author(s):  
Jun Xie ◽  
Jizhou Tang ◽  
Sijie Sun ◽  
Yuwei Li ◽  
Yi Song ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Volume Fraction ◽  
Transport Model ◽  
Fluid Velocity ◽  
Fracture Propagation ◽  
Propagation Model ◽  
Fluid Viscosity ◽  
Fracture Width ◽  
Proppant Transport ◽  
Penny Shaped Crack

Abstract Slurry, as a proppant-laden fluid for hydraulic fracturing, is pumped into initial perforated cracks to generate a conductive pathway for hydrocarbon movement. Recently, numerous studies have been done to investigate mechanisms of proppant transport within vertical fractures. However, the distribution of proppant during stimulation becomes much more complicated if bedding planes (BPs), natural fractures (NFs) or other discontinuities pervasively distributed throughout the formation. Thus, how to capture the transport and placement mechanisms of proppant particles in the opened BPs becomes a significant issue. In this paper, we propose a closed-form continuous proppant transport model based on the conservation of total proppant volume and sedimentation of proppant particles. This model enables to integrate with the fluid flow section of a 3-D hydro-mechanical coupled fracture propagation model and then predict the distribution of proppant velocity and slurry volume fraction within a dynamic fracture network. Stokes’ law is applied to determine the sedimentation velocity. In the fracture propagation model, rock deformation is governed by the analytical solution of penny-shaped crack to determine fracture width. Fluid flow is characterized by finite differentiation scheme and then the fluid velocity is obtained. These two parameters above are inputs for the proppant transport model and both slurry viscosity and density are updated in this step. Afterwards, both fracture width and fluid velocity would be altered in the fracture model. Analysis of the proppant distribution within crossing-shaped fracture is conducted to study mechanisms of proppant transport along opened BPs. From our numerical analysis, we find that the distribution of proppant concentration is independent with the fluid viscosity, but highly dependent on the volume fraction of pumping slurry, under a given pumping pressure. Due to the difference of viscosity and proppant volume fraction at locations of upper and lower BPs, we observe that two symmetric BPs are unevenly opened, with different channel length along BP. Moreover, the width of opened upper BP is much smaller than that of opened lower BP as a result of discrepancy of proppant sedimentation. Last but not the least, a criterion of flow bed mobilization is established for dynamically tracking the sedimentation along the BP. Then the effect of different parameters (such as proppant size, proppant density, fluid viscosity, injection rate) on proppant distribution along opened BPs is also studied. Our model fully considers the proppant transport and settlement, proppant bed formation and interaction between fracture and proppant, which helps to predict the influence of proppant during fracturing treatment. Additionally, our model is also capable of dynamically tracking the settlement of proppant along opened BPs.

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