Laboratory Investigation of Flow Paths in 3D Self-Affine Fractures with Lattice Boltzmann Simulations

Li, Jiawei; Cherubini, Claudia; Galindo‐Torres, S. A.; Zi, Li; Pastore, Nicola; Li, Ling

doi:10.3390/en11010168

Cited by 9 publications

(6 citation statements)

References 67 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Different flow regimes, e.g., droplet, rivulet, and film flow, can coexist even in controlled settings and are difficult to cast into unified conceptual frameworks (Ghezzehei, 2004). In well-controlled analog percolation experiments, the fracture-specific formation of flow modes and instabilities (Jones et al, 2018;Li et al, 2018) and the role of unsaturated fracture intersections on partitioning behavior has been investigated (e.g., Ji et al, 2006;Kordilla et al, 2017;LaViolette et al, 2003;Nicholl and Glass, 2005;Wood et al, 2002Wood et al, , 2005Wood and Huang, 2015), where the applied flow rate controls the stability of a desired flow regime (Towell and Rothfeld, 1966;Schmuki and Laso, 1990). These studies emphasize the importance of fracture intersections as capillary barriers (until steady-state conditions are established), which may induce pulsating flows and act as important integrators for dispersion and recharge processes.…”

mentioning

confidence: 99%

Analogue Fracture Experiments and Analytical Modeling of Unsaturated Percolation Dynamics in Fracture Cascades

Noffz¹,

Dentz

Kordilla³

2019

Vadose Zone Journal

View full text Add to dashboard Cite

Core Ideas Mass redistribution at unsaturated fracture intersections depends on free‐surface flow modes. A Washburn‐type flow regime is recovered via an analytical solution for capillary fracture inflow. A Gaussian transfer function predicts mass partitioning for arbitrary‐sized fracture cascades. Infiltration and recharge dynamics in fractured aquifer systems often strongly deviate from diffuse Darcy–Buckingham type flows due to the existence of a complex gravity‐driven flow component along fractures, fracture networks, and fault zones. The formation of preferential flow paths in the unsaturated or vadose zone can trigger rapid mass fluxes, which are difficult to recover by volume‐effective modeling approaches (e.g., the Richards equation) due to the nonlinear nature of free‐surface flows and mass partitioning processes at unsaturated fracture intersections. In this study, well‐controlled laboratory experiments enabled the isolation of single aspects of the mass redistribution process that ultimately affect travel time distributions across scales. We used custom‐made acrylic cubes (20 by 20 by 20 cm) in analog percolation experiments to create simple wide‐aperture fracture networks intersected by one or multiple horizontal fractures. A high‐precision multichannel dispenser produced gravity‐driven free‐surface flow (droplets or rivulets) at flow rates ranging from 1 to 5 mL min−1. Total inflow rates were kept constant while the fluid was injected via 15 (droplet flow) or three inlets (rivulet flow) to reduce the impact of erratic flow dynamics. Normalized fracture inflow rates were calculated and compared for aperture widths of 1 and 2.5 mm. A higher efficiency in filling an unsaturated fracture by rivulet flow observed in former studies was confirmed. The onset of a capillary‐driven Washburn‐type flow was determined and recovered by an analytical solution. To upscale the dynamics and enable the prediction of mass partitioning for arbitrary‐sized fracture cascades, a Gaussian transfer function was derived that reproduces the repetitive filling of fractures, where rivulet flow is the prevailing regime. Results show good agreement with experimental data for all tested aperture widths.

show abstract

mentioning

confidence: 99%

Analogue Fracture Experiments and Analytical Modeling of Unsaturated Percolation Dynamics in Fracture Cascades

Noffz¹,

Dentz

Kordilla³

2019

Vadose Zone Journal

View full text Add to dashboard Cite

show abstract

“…Kishida et al [12] suggested that the applicability of the Reynolds equation is limited to low Re conditions and smooth fracture walls, so that the flow rate and local velocity components perpendicular to the nominal fracture plane are sufficiently low. In order to solve this problem, some researchers [13][14][15] have investigated the role of the aperture length and its spatial variation on the distribution of flow rates along the fracture. They reported that the characterization of fracture geometry, such as mismatch length and fractal dimension, led to the change in flow rates within the fracture, which can be visualized using a transparent fracture.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation on Water Seepage through Transparent Synthetic Rough-Walled Fractures

Ranjbar

Cherubini

Pastore

2022

Water

Self Cite

View full text Add to dashboard Cite

One of the impacts of climate changes nowadays is the increase in the frequency of high-intensity rainfall events alternating with extreme dry periods, which affect the components of the hydrologic cycle, such as runoff, infiltration, and aquifer recharge. Several experimental investigations and theoretical studies have demonstrated that infiltration flow in fractured media can develop along preferential pathways. However, the prediction of infiltration phenomena in fractured media still remains an open issue. This, together with erratic rainfall patterns due to climate changes, affects the prediction of aquifer recharge and contaminant transport in fractured aquifers. The present work contributes to reducing this research gap by means of experimental investigation and forecast analysis, with a focus on the geometrical properties of single fractures and their influence on flow patterns. Several fracture surfaces based on different fractal dimensions, standard deviations, and mismatch lengths were designed using the SynFrac model and were generated by 3D printing technology. The results revealed that the fracture’s fractal dimension has a significant impact on the number of flow paths, while the fracture inclination only increases the number of intermediate preferential channels, and, hence, modifies the flow rate distribution over the fracture outlet. Additionally, the change in the inclination angle of the dry fracture from 55 to 65 degrees resulted in an 8% reduction in the mean width of first flow path. A sensitivity analysis using an M5 tree indicates that there is a linear relationship between flow rate and the exponential form of the fractal dimension. The location of flow channels is a function of fracture fractal dimension, and the influence of mismatch length on their location is negligible. Finally, an accurate prediction algorithm with a Nash value of 0.81 was developed using Wavelet transform in order to estimate the time series of periodic flow rates over the fracture outlet.

show abstract

“…Another study shows that with the increase of fracture roughness, the eddy volumes become larger and the effective hydraulic conductivities decreases in rough fractures [52]. An experiment has been designed for the investigation of water flow through fractures with rough surfaces that are generated by 3D printing technology and then the experimental results are compared with simulation results from LBM [53].…”

Section: Introductionmentioning

confidence: 99%

Laboratory Investigation of Flow Paths in 3D Self-Affine Fractures with Lattice Boltzmann Simulations

Cited by 9 publications

References 67 publications

Analogue Fracture Experiments and Analytical Modeling of Unsaturated Percolation Dynamics in Fracture Cascades

Analogue Fracture Experiments and Analytical Modeling of Unsaturated Percolation Dynamics in Fracture Cascades

Experimental Investigation on Water Seepage through Transparent Synthetic Rough-Walled Fractures

Numerical investigation of liquid and supercritical CO2 flow behaviors through 3D self-affine rough fractures

Contact Info

Product

Resources

About