Roughness decomposition and nonlinear fluid flow in a single rock fracture

Zou, Liangchao; Jing, Lanru; Cvetković, Vladimir

doi:10.1016/j.ijrmms.2015.01.016

Cited by 230 publications

(112 citation statements)

References 47 publications

(77 reference statements)

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“…The main flow channel becomes narrow due to the expansion of the eddy domain. Several previous works [28][29][30][31][32] showed similar results for the growth of eddies due to the increasing Reynolds number. At high Reynolds number (Re=170), it can be seen clearly that the eddy-controlled domain occupies a large portion of the fracture.…”

Section: Flow Field and Eddies Formationsupporting

confidence: 65%

Pore-Scale Modeling of Mixing-Induced Reaction Transport through a Single Self-Affine Fracture

et al. 2018

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This pore-scale modeling study in single self-affine fractures showed that the heterogeneous flow field had a significant influence on the mixing-induced reaction transport. We generated the single self-affine fracture by the successive random additions (SRA) technique. The pore-scale model was developed by coupling the Navier-Stoke equation (NSE) and advection-diffusion equation with reaction (ADER). Eddies were captured in the self-affine fracture due to the increasing Reynolds number and the sudden expansion of aperture. The flux-weighted breakthrough curves (BTCs) of reaction product showed the typical non-Fickian characteristics (i.e., "early arrival" and "heavy tail"). It was found that the reactant was involved in eddies and then reacted inside the eddy-controlled domain. Consequently, eddies played a significant role in delaying the mass exchange process between the eddycontrolled domain and the main flow channel, which resulted in the "heavy tail" in BTCs. As the Reynolds number increased, the breakthrough time increased while the concentration peaks of BTCs decreased. Furthermore, the dilution index presenting the exponential of the Shannon entropy of a concentration probability distribution was used to quantify the degree of reactant mixing. The results showed that the quantification of dilution for nonreaction transport was in good agreement with the outcomes of mixing-induced reaction transport. The high Reynolds number and Peclet number had a negative influence on the mixing process at the early time whereas they led to the enhanced mixing process at the late time.

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Section: Flow Field and Eddies Formationsupporting

confidence: 65%

Pore-Scale Modeling of Mixing-Induced Reaction Transport through a Single Self-Affine Fracture

et al. 2018

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“…Navier-Stokes Equations. The flow of incompressible Newtonian fluid is governed by the NS equations, written in a tensor form as [79][80][81] (…”

Section: Governing Equations Of Fluid Flow In Fracturesmentioning

confidence: 99%

“…Besides, the rougher fracture surface contributes to the longer flow paths that a particle moves within fractures, resulting in a weaker conductivity/permeability if the same pressure difference is applied on the opposing boundaries [36,77,122,123]. The previous works have shown that the fracture surface roughness, especially the secondary roughness, plays a significant role on the nonlinear flow properties of rock fractures, because the eddy flow occurs due to the surface roughness [79]. Wang et al [124] established a series of 3D self-affine rock fractures using the successive random additions (SPA) method, in which the geometry of fracture surface is fractal [125,126].…”

Section: Effect Of Fracture Surface Roughnessmentioning

confidence: 99%

A Review of Critical Conditions for the Onset of Nonlinear Fluid Flow in Rock Fractures

Jiang

2017

Geofluids

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Selecting appropriate governing equations for fluid flow in fractured rock masses is of special importance for estimating the permeability of rock fracture networks. When the flow velocity is small, the flow is in the linear regime and obeys the cubic law, whereas when the flow velocity is large, the flow is in the nonlinear regime and should be simulated by solving the complex NavierStokes equations. The critical conditions such as critical Reynolds number and critical hydraulic gradient are commonly defined in the previous works to quantify the onset of nonlinear fluid flow. This study reviews the simplifications of governing equations from the Navier-Stokes equations, Stokes equation, and Reynold equation to the cubic law and reviews the evolutions of critical Reynolds number and critical hydraulic gradient for fluid flow in rock fractures and fracture networks, considering the influences of shear displacement, normal stress and/or confining pressure, fracture surface roughness, aperture, and number of intersections. This review provides a reference for the engineers and hydrogeologists especially the beginners to thoroughly understand the nonlinear flow regimes/mechanisms within complex fractured rock masses.

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“…It has been well recognized, however, that the linear Darcy's law is not always adequate to describe the flow behaviors in natural fractures. Typical characteristics of natural rock fractures include rough walls and asperity contact [2,3], and non-Darcy flow may occur as a result of nonnegligible inertial losses. Previous experimental work demonstrated that Darcy's law fails to predict pressure drops in fractures when inertial effects are relevant before the fully developed turbulence [4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Non-Darcy Flow Experiments of Water Seepage through Rough-Walled Rock Fractures

Niu

Yuan

et al. 2018

Geofluids

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The knowledge of flow phenomena in fractured rocks is very important for groundwater-resources management in hydrogeological engineering. The most commonly used tool to approximate the non-Darcy behavior of the flow velocity is the well-known Forchheimer equation, deploying the "inertial" coefficient that can be estimated experimentally. Unfortunately, the factor of roughness is imperfectly considered in the literature. In order to do this, we designed and manufactured a seepage apparatus that can provide different roughness and aperture in the test; the rough fracture surface is established combining JRC and 3D printing technology. A series of hydraulic tests covering various flows were performed. Experimental data suggest that Forchheimer coefficients are to some extent affected by roughness and aperture. At last, favorable semiempirical Forchheimer equation which can consider fracture aperture and roughness was firstly derived. It is believed that such studies will be quite useful in identifying the limits of applicability of the well-known "cubic law," in further improving theoretical/numerical models associated with fluid flow through a rough fracture.

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Roughness decomposition and nonlinear fluid flow in a single rock fracture

Cited by 230 publications

References 47 publications

Pore-Scale Modeling of Mixing-Induced Reaction Transport through a Single Self-Affine Fracture

Pore-Scale Modeling of Mixing-Induced Reaction Transport through a Single Self-Affine Fracture

A Review of Critical Conditions for the Onset of Nonlinear Fluid Flow in Rock Fractures

Non-Darcy Flow Experiments of Water Seepage through Rough-Walled Rock Fractures

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