Numerical investigation of the possibility of macroscopic turbulence in porous media: a direct numerical simulation study

2015 ◽  
Vol 766 ◽  
pp. 76-103 ◽  
Author(s):  
Y. Jin ◽  
M.-F. Uth ◽  
A. V. Kuznetsov ◽  
H. Herwig
Keyword(s):  
Numerical Simulation ◽  
Porous Medium ◽  
Porous Media ◽  
Direct Numerical Simulation ◽  
Turbulent Flow ◽  
Flow In Porous Media ◽  
Minimum Size ◽  
Solid Matrix ◽  
Pore Scale ◽  
Turbulent Structures

AbstractWhen a turbulent flow in a porous medium is determined numerically, the crucial question is whether turbulence models should account only for turbulent structures restricted in size to the pore scale or whether the size of turbulent structures could exceed the pore scale. The latter would mean the existence of macroscopic turbulence in porous media, when turbulent eddies exceed the pore size. In order to determine the real size of turbulent structures in a porous medium, we simulated the turbulent flow by direct numerical simulation (DNS) calculations, thus avoiding turbulence modelling of any kind. With this study, which for the first time uses DNS calculations, we provide benchmark data for turbulent flow in porous media. Since perfect DNS calculations require the resolution of scales down to the Kolmogorov scale, often only approximate DNS solutions can be obtained, especially for high Reynolds numbers. This is accounted for by using and comparing two different DNS approaches, a finite volume method (FVM) with grid refinement towards the wall and a lattice Boltzmann method (LBM) with equal grid distribution. The solid matrix was simulated by a large number of rectangular bars arranged periodically. The number of bars in the solution domain with periodic boundary conditions was reduced systematically until a minimum size was found that does not suppress any large-scale turbulent structures. Two-point correlations, integral length scales and energy spectra were determined in order to answer the question of whether or not macroscopic turbulence can be found in porous media.

scholarly journals Direct Numerical Simulation of Pore-Scale Trapping Events During Capillary-Dominated Two-Phase Flow in Porous Media

2021 ◽  
Author(s):  
Mosayeb Shams ◽  
Kamaljit Singh ◽  
Branko Bijeljic ◽  
Martin J. Blunt
Keyword(s):  
Numerical Simulation ◽  
Porous Media ◽  
Direct Numerical Simulation ◽  
Complex Geometry ◽  
Flow In Porous Media ◽  
Pore Scale ◽  
Contact Lines ◽  
Two Phase ◽  
X Ray ◽  
Aspect Ratios

AbstractThis study focuses on direct numerical simulation of imbibition, displacement of the non-wetting phase by the wetting phase, through water-wet carbonate rocks. We simulate multiphase flow in a limestone and compare our results with high-resolution synchrotron X-ray images of displacement previously published in the literature by Singh et al. (Sci Rep 7:5192, 2017). We use the results to interpret the observed displacement events that cannot be described using conventional metrics such as pore-to-throat aspect ratio. We show that the complex geometry of porous media can dictate a curvature balance that prevents snap-off from happening in spite of favourable large aspect ratios. We also show that pinned fluid-fluid-solid contact lines can lead to snap-off of small ganglia on pore walls; we propose that this pinning is caused by sub-resolution roughness on scales of less than a micron. Our numerical results show that even in water-wet porous media, we need to allow pinned contacts in place to reproduce experimental results.

scholarly journals Symmetry breaking of turbulent flow in porous media composed of periodically arranged solid obstacles

2021 ◽  
Vol 929 ◽  
Author(s):  
Vishal Srikanth ◽  
Ching-Wei Huang ◽  
Timothy S. Su ◽  
Andrey V. Kuznetsov
Keyword(s):  
Numerical Simulation ◽  
Porous Medium ◽  
Porous Media ◽  
Symmetry Breaking ◽  
Turbulent Flow ◽  
Vortex Shedding ◽  
Flow Instability ◽  
Flow In Porous Media ◽  
Turbulent Regime ◽  
Solid Obstacles

The focus of this paper is a numerical simulation study of the flow dynamics in a periodic porous medium to analyse the physics of a symmetry-breaking phenomenon, which causes a deviation in the direction of the macroscale flow from that of the applied pressure gradient. The phenomenon is prominent in the range of porosity from 0.43 to 0.72 for circular solid obstacles. It is the result of the flow instabilities formed when the surface forces on the solid obstacles compete with the inertial force of the fluid flow in the turbulent regime. We report the origin and mechanism of the symmetry-breaking phenomenon in periodic porous media. Large-eddy simulation (LES) is used to simulate turbulent flow in a homogeneous porous medium consisting of a periodic, square lattice arrangement of cylindrical solid obstacles. Direct numerical simulation is used to simulate the transient stages during symmetry breakdown and also to validate the LES method. Quantitative and qualitative observations are made from the following approaches: (1) macroscale momentum budget and (2) two- and three-dimensional flow visualization. The phenomenon draws its roots from the amplification of a flow instability that emerges from the vortex shedding process. The symmetry-breaking phenomenon is a pitchfork bifurcation that can exhibit multiple modes depending on the local vortex shedding process. The phenomenon is observed to be sensitive to the porosity, solid obstacle shape and Reynolds number. It is a source of macroscale turbulence anisotropy in porous media for symmetric solid-obstacle geometries. In the macroscale, the principal axis of the Reynolds stress tensor is not aligned with any of the geometric axes of symmetry, nor with the direction of flow. Thus, symmetry breaking in porous media involves unresolved flow physics that should be taken into consideration while modelling flow inhomogeneity in the macroscale.

Direct numerical simulation of pore scale particle-water-oil transport in porous media

2019 ◽  
Vol 180 ◽  
pp. 159-175 ◽  
Author(s):  
Junwei Su ◽  
Guoliang Chai ◽  
Le Wang ◽  
Weidong Cao ◽  
Jinbiao Yu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Porous Media ◽  
Direct Numerical Simulation ◽  
Pore Scale ◽  
Oil Transport ◽  
Transport In Porous Media ◽  
Scale Particle

Comparison of Competing Invasion-Percolation Models for Simulation of Multiphase Flow in Porous Media 

2021 ◽  
Author(s):  
Ishani Banerjee ◽  
Anneli Guthke ◽  
Kevin Mumford ◽  
Wolfgang Nowak
Keyword(s):  
Porous Medium ◽  
Porous Media ◽  
Gas Flow ◽  
Flow Regimes ◽  
Flow In Porous Media ◽  
Invasion Percolation ◽  
Pore Scale ◽  
Discontinuous Flow ◽  
Model Version ◽  
Water Saturated

<p>Invasion-Percolation (IP) models are used to simulate multiphase flow in porous media across various scales (from pore-scale IP to Macro-IP). Numerous variations of IP models have emerged; here we are interested in simulating gas flow in a water-saturated porous medium. Gas flow in porous media occurs either as a continuous or as a discontinuous flow, depending on the rate of flow and the nature of the porous medium. A particular IP model version may be well suited for predictions in a specific gas flow regime, but not applicable to other regimes. Our research aims to compare various macro-scale versions of IP models existing in the literature and rank their performance in relevant gas flow regimes.</p><p>We test the performance of Macro-IP models on a range of gas-injection rates in water-saturated sand experiments, including both continuous and discontinuous flow regimes. The experimental data is obtained as a time series of images using the light transmission technique. To represent pore-scale heterogeneities of sand, we let each model version run on several random realizations of the initial entry pressure field. As a metric for ranking the models, we introduce a diffused version of the so-called Jaccard index (adapted from image analysis and object recognition). We average this metric over time and over all realizations per model version to evaluate each model’s overall performance. This metric may also be used to calibrate model parameters such as gas saturation. </p><p>Our proposed approach evaluates the performance of competing IP model versions in different gas-flow regimes objectively and quantitatively, and thus provides guidance on their applicability under specific conditions. Moreover, our comparison method is not limited to gas-water phase systems in porous media but generalizes to any modelling situation accompanied by spatially and temporally highly resolved data.</p>

A General Macroscopic Model for Turbulent Flow in Porous Media

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Nima F. Jouybari ◽  
Mehdi Maerefat ◽  
T. Staffan Lundström ◽  
Majid E. Nimvari ◽  
Zahra Gholami
Keyword(s):  
Porous Media ◽  
Turbulent Flow ◽  
Present Model ◽  
Flow Characteristics ◽  
Flow In Porous Media ◽  
Macroscopic Model ◽  
Solid Matrix ◽  
Turbulent Regime ◽  
Rod Bundles ◽  
Capillary Model

The present study deals with the generalization of a macroscopic turbulence model in porous media using a capillary model. The additional source terms associated with the production and dissipation of turbulent kinetic energy due to the presence of solid matrix are calculated using the capillary model. The present model does not require any prior pore scale simulation of turbulent flow in a specific porous geometry in order to close the macroscopic turbulence equations. Validation of the results in packed beds, periodic arrangement of square cylinders, synthetic foams, and longitudinal flows such as pipes, channels, and rod bundles against available data in the literature reveals the ability of the present model in predicting turbulent flow characteristics in different types of porous media. Transition to the fully turbulent regime in porous media and different approaches to treat this phenomenon are also discussed in the present study. Finally, the general model is modified so that it can be applied to lower Reynolds numbers below the range of fully turbulent regime in porous media.

Direct numerical simulation of convective heat transfer of supercritical pressure in a vertical tube with buoyancy and thermal acceleration effects

2021 ◽  
Vol 927 ◽  
Author(s):  
Y.L. Cao ◽  
R.N. Xu ◽  
J.J. Yan ◽  
S. He ◽  
P.X. Jiang
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Turbulent Flow ◽  
Vertical Tube ◽  
Supercritical Pressure ◽  
Dominant Factor ◽  
Turbulent Structures ◽  
Flow Acceleration ◽  
Flow And Heat Transfer

Supercritical pressure fluids are widely used in heat transfer and energy systems. The benefit of high heat transfer performance and the successful avoidance of phase change from the use of supercritical pressure fluids are well-known, but the complex behaviours of such fluids owing to dramatic thermal property variations pose strong challenges to the design of heat transfer applications. In this paper, the turbulent flow and heat transfer of supercritical pressure $\textrm {CO}_2$ in a small vertical tube influenced by coupled effects of buoyancy and thermal acceleration are numerically investigated using direct numerical simulation. Both upward and downward flows with an inlet Reynolds number of 3540 and pressure of 7.75 MPa have been simulated and the results are compared with corresponding experimental data. The flow and heat transfer results reveal that under buoyancy and thermal acceleration, the turbulent flow and heat transfer exhibit four developing periods in which buoyancy and thermal acceleration alternately dominate. The results suggest a way to distinguish the dominant factor of heat transfer in different periods and a criterion for heat transfer degradation under the complex coupling of buoyancy and thermal acceleration. An analysis of the orthogonal decomposition and the generative mechanism of turbulent structures indicates that the flow acceleration induces a stretch-to-disrupt mechanism of coherent turbulent structures. The significant flow acceleration can destroy the three-dimensional flow structure and stretch the vortices resulting in dissipation.

Pore-scale direct numerical simulation of particle transport in porous media

2019 ◽  
Vol 199 ◽  
pp. 613-627 ◽  
Author(s):  
Junwei Su ◽  
Guoliang Chai ◽  
Le Wang ◽  
Weidong Cao ◽  
Zhaolin Gu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Porous Media ◽  
Direct Numerical Simulation ◽  
Particle Transport ◽  
Pore Scale ◽  
Transport In Porous Media
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