Numerical Assessment of the Hybrid Approach for Simulating Three-Dimensional Flow and Advective Transport in Fractured Rocks

This study presents a hybrid approach for simulating flow and advective transport dynamics in fractured rocks. The developed hybrid domain (HD) model uses the two-dimensional (2D) triangular mesh for fractures and tetrahedral mesh for the three-dimensional (3D) rock matrix in a simulation domain and allows the system of equations to be solved simultaneously. This study also illustrates the HD model with two numerical cases that focus on the flow and advective transport between the fractures and rock matrix. The quantitative assessments are conducted by comparing the HD results with those obtained from the discrete fracture network (DFN) and equivalent continuum porous medium (ECPM) models. Results show that the HD model reproduces the head solutions obtained from the ECPM model in the simulation domain and heads from the DFN model in the fractures in the first case. The particle tracking results show that the mean particle velocity in the HD model can be 7.62 times higher than that obtained from the ECPM mode. In addition, the developed HD model enables detailed calculations of the fluxes at intersections between fractures and cylinder objects in the case and obtains relatively accurate flux along the intersections. The solutions are the key factors to evaluate the sources of contaminant released from the disposal facility.

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Modelling the variation in the behaviour of pre-fractured rocks subjected to hydraulic fracturing with permeability of the rock matrix using finite-discrete element method

E3S Web of Conferences ◽

10.1051/e3sconf/202020508001 ◽

2020 ◽

Vol 205 ◽

pp. 08001

Author(s):

Shahrzad Roshankhah ◽

Arman K. Nejad ◽

Orlando Teran ◽

Kami Mohammadi

Keyword(s):

Rock Mass ◽

Finite Elements ◽

Hydraulic Fracturing ◽

Discrete Element Method ◽

Fractured Rocks ◽

Discrete Element ◽

Fracture Network ◽

Rock Matrix ◽

Flow Through ◽

Element Method

In this study, we present the results of two-dimensional numerical simulations for the effects of rock matrix permeability on the behaviour of hydraulic fractures in intact and pre-fractured rocks. The simulations are performed using the Finite-Discrete Element Method (FDEM). In this method, the deformation and fluid pressure fields within the porous rock blocks, pre-existing fracture network, and hydraulically induced fractures are calculated through a fully coupled hydromechanical scheme. Furthermore, new fractures can initiate in crack elements located between each pair of finite elements and can propagate in any path that the boundary and loading conditions require according to non-linear fracture mechanics criteria. Fluid channels are also defined between pairs of finite elements simulating the inter-connected flow paths through porous media. Four models of the rock mass are created in this study: (i) homogeneous-impermeable, (ii) homogeneous-permeable, (iii) heterogeneous-impermeable matrix, and (iv) heterogeneous-permeable matrix. Heterogeneous rock masses contain a discrete fracture network (natural fractures) in the rock mass structure. Hydraulic fracturing is modelled in domains of 40×40 m2 with the four different structures and mass transport capacities, and the results are compared to each other. The results highlight the significant effect of diffusive fluid flow through rock blocks, in addition to the flow through fracture network, on the global hydromechanical behaviour of the rock mass. These results help to understand the governing hydromechanical processes taking place in fractured rocks with matrix of different permeability, such as granites, shales, carbonate rocks, and sandstones and the extent of complexities required to model their behaviour to achieve reasonable accuracy.

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Development of Discrete Fracture Network Model Simulator, GeoFlow, for Evaluation of Three Dimensional Channeling Flow

10.2523/13143-ms ◽

2009 ◽

Cited By ~ 2

Author(s):

Takuya Ishibashi ◽

Noriaki Watanabe ◽

Nobuo Hirano ◽

Atsushi Okamoto ◽

Noriyoshi Tsuchiya

Keyword(s):

Network Model ◽

Three Dimensional ◽

Fracture Network ◽

Discrete Fracture Network ◽

Discrete Fracture ◽

Channeling Flow

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Three-dimensional advective transport of volatile organic compounds in ground water beneath an industrial/residential area of Nassau County, New York

10.3133/wri924148 ◽

1995 ◽

Keyword(s):

New York ◽

Volatile Organic Compounds ◽

Ground Water ◽

Organic Compounds ◽

Three Dimensional ◽

Residential Area ◽

Advective Transport ◽

Nassau County ◽

Volatile Organic

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Accelerated Time and High-Resolution 3D Modeling of the Flow and Dispersion of Noxious Substances over a Gigantic Urban Area—The EMERGENCIES Project

Atmosphere ◽

10.3390/atmos12050640 ◽

2021 ◽

Vol 12 (5) ◽

pp. 640

Author(s):

Olivier Oldrini ◽

Patrick Armand ◽

Christophe Duchenne ◽

Sylvie Perdriel ◽

Maxime Nibart

Keyword(s):

High Resolution ◽

Urban Area ◽

3D Modeling ◽

Three Dimensional ◽

Hazardous Materials ◽

Support Tool ◽

On Demand ◽

Simulation Domain ◽

Dimensional Simulation ◽

Atmospheric Release

Accidental or malicious releases in the atmosphere are more likely to occur in built-up areas, where flow and dispersion are complex. The EMERGENCIES project aims to demonstrate the operational feasibility of three-dimensional simulation as a support tool for emergency teams and first responders. The simulation domain covers a gigantic urban area around Paris, France, and uses high-resolution metric grids. It relies on the PMSS modeling system to model the flow and dispersion over this gigantic domain and on the Code_Saturne model to simulate both the close vicinity and the inside of several buildings of interest. The accelerated time is achieved through the parallel algorithms of the models. Calculations rely on a two-step approach: the flow is computed in advance using meteorological forecasts, and then on-demand release scenarios are performed. Results obtained with actual meteorological mesoscale data and realistic releases occurring both inside and outside of buildings are presented and discussed. They prove the feasibility of operational use by emergency teams in cases of atmospheric release of hazardous materials.

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Characterizing Reactive Transport Behavior in a Three-Dimensional Discrete Fracture Network

Transport in Porous Media ◽

10.1007/s11242-021-01568-4 ◽

2021 ◽

Author(s):

Thomas Sherman ◽

Guillem Sole-Mari ◽

Jeffrey Hyman ◽

Matthew R. Sweeney ◽

Daniel Vassallo ◽

...

Keyword(s):

Reactive Transport ◽

Three Dimensional ◽

Fracture Network ◽

Discrete Fracture Network ◽

Transport Behavior ◽

Discrete Fracture

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Lifting restrictions on coherence loss when characterizing non-transparent hypersonic phononic crystals

Scientific Reports ◽

10.1038/s41598-021-96663-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Konrad Rolle ◽

Dmytro Yaremkevich ◽

Alexey V. Scherbakov ◽

Manfred Bayer ◽

George Fytas

Keyword(s):

Frequency Domain ◽

Hybrid Approach ◽

Three Dimensional ◽

Phononic Crystals ◽

Hybrid Technique ◽

Detection Mechanism ◽

Pump Probe ◽

Fabry Perot ◽

Multilayer Stacks ◽

Deposition Techniques

AbstractHypersonic phononic bandgap structures confine acoustic vibrations whose wavelength is commensurate with that of light, and have been studied using either time- or frequency-domain optical spectroscopy. Pulsed pump-probe lasers are the preferred instruments for characterizing periodic multilayer stacks from common vacuum deposition techniques, but the detection mechanism requires the injected sound wave to maintain coherence during propagation. Beyond acoustic Bragg mirrors, frequency-domain studies using a tandem Fabry–Perot interferometer (TFPI) find dispersions of two- and three-dimensional phononic crystals (PnCs) even for highly disordered samples, but with the caveat that PnCs must be transparent. Here, we demonstrate a hybrid technique for overcoming the limitations that time- and frequency-domain approaches exhibit separately. Accordingly, we inject coherent phonons into a non-transparent PnC using a pulsed laser and acquire the acoustic transmission spectrum on a TFPI, where pumped appear alongside spontaneously excited (i.e. incoherent) phonons. Choosing a metallic Bragg mirror for illustration, we determine the bandgap and compare with conventional time-domain spectroscopy, finding resolution of the hybrid approach to match that of a state-of-the-art asynchronous optical sampling setup. Thus, the hybrid pump–probe technique retains key performance features of the established one and going forward will likely be preferred for disordered samples.

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Three–Dimensional Segmentation of Ventricular Heart Chambers from Multi–Slice Computerized Tomography: An Hybrid Approach

Communications in Computer and Information Science - Digital Information and Communication Technology and Its Applications ◽

10.1007/978-3-642-21984-9_25 ◽

2011 ◽

pp. 287-301 ◽

Cited By ~ 5

Author(s):

Antonio Bravo ◽

Miguel Vera ◽

Mireille Garreau ◽

Rubén Medina

Keyword(s):

Computerized Tomography ◽

Hybrid Approach ◽

Three Dimensional ◽

Three Dimensional Segmentation

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Seismic Vertical Component Effects on the Pathology of a Historical Structure, Xana, Located in Greece

Frontiers in Built Environment ◽

10.3389/fbuil.2021.666840 ◽

2021 ◽

Vol 7 ◽

Author(s):

Vasiliki Terzi ◽

Asimina Athanatopoulou

Keyword(s):

Seismic Analysis ◽

Near Field ◽

Three Dimensional ◽

Vertical Component ◽

Element Model ◽

Material Behavior ◽

Initial State ◽

Tensile Cracks ◽

First Case ◽

Three Dimensional Finite Element

The present study aims to investigate the effects of the seismic vertical component on the pathology of Xana monument which is a typical caravanserai, constructed circa 1375–1385 and is located in the archeological site of the municipality of Trainapoulis, Greece. The monument’s plan is rectangular and the three-leaf masonry circumferential walls support a hemicylindrical dome constructed by bricks and mortar. The structure consisted of two consecutive parts: one for the travelers and one for the animals. Nowadays, the triangular roof, that covered the structure, and the first part of the monument do not exist. Xana suffers tensile cracks along the interior surface of the dome, a vertical fracture located on the northern wall and vertical tensile cracks located at the openings. A three-dimensional finite element model of the initial state of Xana is constructed. Non-linear material behavior is taken into account as well as soil-structure interaction effects. An adequate number of near-field earthquake events has been used, taking into account that they are related to significant vertical components. The structural seismic analysis is conducted for two cases. The first case refers to the action of the two horizontal-component of ground motions while the second one takes into account the three translational seismic components. The pathology estimation reveals important information concerning the structural effects due to vertical accelerations.

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