scholarly journals Pattern formation and coarsening dynamics in three-dimensional convective mixing in porous media

2013 ◽  
Vol 371 (2004) ◽  
pp. 20120355 ◽  
Author(s):  
Xiaojing Fu ◽  
Luis Cueto-Felgueroso ◽  
Ruben Juanes
Keyword(s):  
Boundary Layer ◽  
Pattern Formation ◽  
Cellular Network ◽  
Gravitational Instability ◽  
Three Dimensional ◽  
Concentration Field ◽  
Convective Mixing ◽  
Long Term Storage ◽  
Diffusive Boundary ◽  
Dimensional Simulation

Geological carbon dioxide (CO 2 ) sequestration entails capturing and injecting CO 2 into deep saline aquifers for long-term storage. The injected CO 2 partially dissolves in groundwater to form a mixture that is denser than the initial groundwater. The local increase in density triggers a gravitational instability at the boundary layer that further develops into columnar plumes of CO 2 -rich brine, a process that greatly accelerates solubility trapping of the CO 2 . Here, we investigate the pattern-formation aspects of convective mixing during geological CO 2 sequestration by means of high-resolution three-dimensional simulation. We find that the CO 2 concentration field self-organizes as a cellular network structure in the diffusive boundary layer at the top boundary. By studying the statistics of the cellular network, we identify various regimes of finger coarsening over time, the existence of a non-equilibrium stationary state, and a universal scaling of three-dimensional convective mixing.

Direct simulation of evolution and control of three-dimensional instabilities in attachment-line boundary layers

1995 ◽  
Vol 291 ◽  
pp. 369-392 ◽  
Author(s):  
Ronald D. Joslin
Keyword(s):  
Boundary Layer ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Plate Boundary ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Computationally Efficient ◽  
Simulation Results ◽  
Dimensional Simulation ◽  
Attachment Line

The spatial evolution of three-dimensional disturbances in an attachment-line boundary layer is computed by direct numerical simulation of the unsteady, incompressible Navier–Stokes equations. Disturbances are introduced into the boundary layer by harmonic sources that involve unsteady suction and blowing through the wall. Various harmonic-source generators are implemented on or near the attachment line, and the disturbance evolutions are compared. Previous two-dimensional simulation results and nonparallel theory are compared with the present results. The three-dimensional simulation results for disturbances with quasi-two-dimensional features indicate growth rates of only a few percent larger than pure two-dimensional results; however, the results are close enough to enable the use of the more computationally efficient, two-dimensional approach. However, true three-dimensional disturbances are more likely in practice and are more stable than two-dimensional disturbances. Disturbances generated off (but near) the attachment line spread both away from and toward the attachment line as they evolve. The evolution pattern is comparable to wave packets in flat-plate boundary-layer flows. Suction stabilizes the quasi-two-dimensional attachment-line instabilities, and blowing destabilizes these instabilities; these results qualitatively agree with the theory. Furthermore, suction stabilizes the disturbances that develop off the attachment line. Clearly, disturbances that are generated near the attachment line can supply energy to attachment-line instabilities, but suction can be used to stabilize these instabilities.

Three-Dimensional Simulation for Diffusion of Matter in Compound Round Jet by Particle Method

2003 ◽  
Author(s):  
Tomomi Uchiyama ◽  
Akihito Ichikawa
Keyword(s):  
Three Dimensional ◽  
Concentration Field ◽  
Particle Method ◽  
Vortex Method ◽  
Vortical Flow ◽  
Round Jet ◽  
The Mean ◽  
Dimensional Simulation ◽  
Mean Concentration ◽  
Good Agreement

The diffusion of matter in compound round jet is simulated by three-dimensional particle method. The flow field is calculated with a vortex method, whereas the concentration field is simulated through a particle method analogous to the vortex method. It is shown that the concentration distribution yielded by the three-dimensional vortical flow is in good agreement with the experimental one obtained by the flow visualization. The mean concentration is confirmed to be in the self-preservation state.

Radiative Three-Dimensional Flow with Chemical Reaction

2016 ◽  
Vol 14 (1) ◽  
pp. 79-91 ◽  
Author(s):  
Tasawar Hayat ◽  
Taseer Muhammad ◽  
Sabir Ali Shehzad ◽  
Ahmed Alsaedi ◽  
Falleh Al-Solamy
Keyword(s):  
Boundary Layer ◽  
Brownian Motion ◽  
Chemical Reaction ◽  
Three Dimensional ◽  
Concentration Field ◽  
Lewis Number ◽  
Magnetic Reynolds Number ◽  
Dimensional Boundary ◽  
Layer Flow ◽  
Influential Parameters

AbstractWe discuss the three-dimensional boundary layer flow of Maxwell nanofluid in the present article. The flow is caused due to bidirectional stretching surface. An applied magnetic field is taken into account. Heat and mass transfer characteristics are considered in the presence of thermal radiation, Brownian motion, thermophoresis and chemical reaction effects. Mathematical modelling is made under a low magnetic Reynolds number and Rosseland’s approximation. Expressions of series solutions for velocities, temperature and concentration are developed. Impacts of influential parameters on the temperature and concentration are sketched and examined. Numerical values of local Nusselt and Sherwood numbers are computed and analyzed. We found that an increase in thermophoresis and Brownian motion parameters enhanced the temperature field and thermal boundary layer thickness. The concentration field reduced gradually when we enhance the values of Lewis number and chemical reaction parameter. The values of local Nusselt number are higher for a larger radiation parameter.

The impact of geochemistry on convective mixing in a gravitationally unstable diffusive boundary layer in porous media: CO2 storage in saline aquifers

2011 ◽  
Vol 673 ◽  
pp. 480-512 ◽  
Author(s):  
KARIM GHESMAT ◽  
HASSAN HASSANZADEH ◽  
JALAL ABEDI
Keyword(s):  
Carbon Dioxide ◽  
Boundary Layer ◽  
Porous Media ◽  
Saline Aquifers ◽  
Diffusive Boundary Layer ◽  
Convective Mixing ◽  
Geochemical Reactions ◽  
Diffusive Boundary ◽  
The Stability ◽  
The Impact

The storage of carbon dioxide and acid gases in deep geological formations is considered a promising option for mitigation of greenhouse gas emissions. An understanding of the primary mechanisms such as convective mixing and geochemistry that affect the long-term geostorage process in deep saline aquifers is of prime importance. First, a linear stability analysis of an unstable diffusive boundary layer in porous media is presented, where the instability occurs due to a density difference between the carbon dioxide saturated brine and the resident brine. The impact of geochemical reactions on the stability of the boundary layer is examined. The equations are linearised, and the obtained system of eigenvalue problems is solved numerically. The linear stability results have revealed that geochemistry stabilises the boundary layer as reaction consumes the dissolved carbon dioxide and makes the density profile, as the source of instability, more uniform. A detailed physical discussion is also presented with an examination of vorticity and concentration eigenfunctions and streamlines' contours to reveal how the geochemical reaction may affect the hydrodynamics of the process. We also investigate the effects of the Rayleigh number and the diffusion time on the stability of a boundary layer coupled with geochemical reactions. Nonlinear direct numerical simulations are also presented, in which the evolution of density-driven instabilities for different reaction rates is discussed. The development of instability is precisely studied for various scenarios. The results indicate that the boundary layer will be more stable for systems with a higher rate of reaction. However, our quantitative analyses show that more carbon dioxide may be removed from the supercritical free phase as the measured flux at the boundary is always higher for flow systems coupled with stronger geochemical reactions.

scholarly journals Diffusion or advection? Mass transfer and complex boundary layer landscapes of the brown alga Fucus vesiculosus

2017 ◽  
Vol 14 (128) ◽  
pp. 20161015 ◽  
Author(s):  
Mads Lichtenberg ◽  
Rasmus Dyrmose Nørregaard ◽  
Michael Kühl
Keyword(s):  
Boundary Layer ◽  
Mass Transfer ◽  
Three Dimensional ◽  
Fucus Vesiculosus ◽  
Pressure Gradients ◽  
Three Dimensional Mapping ◽  
Microbe Interactions ◽  
Complex Boundary ◽  
Diffusive Boundary ◽  
Set Up

The role of hyaline hairs on the thallus of brown algae in the genus Fucus is long debated and several functions have been proposed. We used a novel motorized set-up for two-dimensional and three-dimensional mapping with O 2 microsensors to investigate the spatial heterogeneity of the diffusive boundary layer (DBL) and O 2 flux around single and multiple tufts of hyaline hairs on the thallus of Fucus vesiculosus. Flow was a major determinant of DBL thickness, where higher flow decreased DBL thickness and increased O 2 flux between the algal thallus and the surrounding seawater. However, the topography of the DBL varied and did not directly follow the contour of the underlying thallus. Areas around single tufts of hyaline hairs exhibited a more complex mass-transfer boundary layer, showing both increased and decreased thickness when compared with areas over smooth thallus surfaces. Over thallus areas with several hyaline hair tufts, the overall effect was an apparent increase in the boundary layer thickness. We also found indications for advective O 2 transport driven by pressure gradients or vortex shedding downstream from dense tufts of hyaline hairs that could alleviate local mass-transfer resistances. Mass-transfer dynamics around hyaline hair tufts are thus more complex than hitherto assumed and may have important implications for algal physiology and plant–microbe interactions.

Three-Dimensional Simulation of Planar Solid Oxide Fuel Cell Stack

2008 ◽  
Vol 128 (2) ◽  
pp. 459-466 ◽  
Author(s):  
Yoshitaka Inui ◽  
Tadashi Tanaka ◽  
Tomoyoshi Kanno
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Three Dimensional ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Fuel Cell Stack ◽  
Dimensional Simulation
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