Article
Mechanics
Didier Lasseux, Francisco J. Valdes-Parada
Summary: A closed expression is proposed to calculate the average pressure difference in two-phase flow in porous media. This equation takes into account the pressure gradient, body forces, and interfacial effects in each phase, and is applicable to situations where the fluid-fluid interface is not steady. The accuracy of this expression is validated by comparing it with direct numerical simulations in a model porous structure.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Geosciences, Multidisciplinary
Yihuai Zhang, Branko Bijeljic, Ying Gao, Qingyang Lin, Martin J. Blunt
Summary: The study focuses on the pressure difference during two-phase flow across a sandstone sample with varying injection rates and fractional flows of water. It was observed that there is a transition from linear to non-linear flow with the power-law exponent depending on the fractional flow. By using energy balance, the onset of intermittency for a range of fractional flows, fluid viscosities, and rock types was accurately predicted.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Mechanics
Jessica Sanchez-Vargas, Francisco J. Valdes-Parada, Mauricio A. Trujillo-Roldan, Didier Lasseux
Summary: A closed macroscopic model for quasi-steady, inertial, incompressible, two-phase generalised Newtonian flow in rigid and homogeneous porous media is derived by upscaling the pore-scale equations. The derived model includes macroscopic equations for mass and momentum balance as well as an expression for the macroscopic pressure difference between the two fluid phases. The predictions from the upscaled models are in excellent agreement with direct numerical simulations, confirming the validity of the derived macroscopic models.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
Linlin Fei, Feifei Qin, Jianlin Zhao, Dominique Derome, Jan Carmeliet
Summary: A mesoscopic lattice Boltzmann model is used to simulate isothermal two-component evaporation in porous media. The model incorporates a pseudopotential multiphase model with two components, and employs a cascaded collision operator for improved numerical performance. The model is validated through theoretical analysis and microfluidic experiments. The effects of inflow vapour concentration and contact angle on the evaporation process are investigated, and a scaling formulation for the evaporation rate is proposed.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
Zhongzheng Wang, Jean-Michel Pereira, Emilie Sauret, Yixiang Gan
Summary: The irregular growth of invading fluid during the imbibition process in two-dimensional regular porous media is studied. A phase diagram describing the dominance of different invasion events is proposed, and excellent agreement is observed on the transition boundary from faceted and compact displacement patterns to irregular and dendritic invasion morphologies.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Didier Lasseux, Francisco J. Valdes-Parada
Summary: This study presents a closed macroscopic model for immiscible two-phase flow in a rigid and homogeneous porous medium. The derived equations are obtained from the pore-scale equations and the model is validated through comparisons with direct numerical simulations.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Water Resources
Catherine Spurin, Tom Bultreys, Maja Ruecker, Gaetano Garfi, Christian M. Schleputz, Vladimir Novak, Steffen Berg, Martin J. Blunt, Samuel Krevor
Summary: Intermittent fluid flow has been found to play a significant role in the transport of subsurface multiphase fluids, impacting properties like relative permeability. Higher capillary numbers lead to increased volume of intermittent fluid fluctuations, expanding the flow network and reducing the influence of inertial forces on flow. The study shows that intermittent pathway flow is energetically positioned between laminar and turbulent flow through connected pathways, with implications on relative permeability.
ADVANCES IN WATER RESOURCES
(2021)
Article
Mechanics
Yihuai Zhang, Branko Bijeljic, Martin J. Blunt
Summary: This article reveals the nonlinear and intermittent features of multiphase flow in porous materials through experiments and simulations, and accurately predicts the start of intermittent flow using an energy balance method. The pore-scale explanation based on the periodic filling of critical flow pathways is further validated through X-ray imaging.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Engineering, Petroleum
Xiang Rao, Hui Zhao, Yina Liu
Summary: This paper proposes a meshless numerical modeling method called mesh-free discrete fracture model (MFDFM) for fractured reservoirs based on the newly developed extended finite volume method (EFVM). MFDFM discretizes the reservoir domain with fracture networks using matching and nonmatching point cloud generation algorithms, avoiding the challenges of traditional mesh-based methods. It derives the EFVM discrete scheme of the governing equations and constructs various connections between matrix nodes and fracture nodes, calculating their transmissibilities. The global nonlinear equations can be solved by existing nonlinear solvers, making it easier to form a general purpose MFDFM-based fractured reservoir numerical simulator. Numerical test cases show that MFDFM performs well under different conditions and outperforms other models.
Article
Mechanics
Anjali, Arshan Khan, P. Bera
Summary: This study investigates the thermal convection of Poiseuille flow in an anisotropic and inhomogeneous porous domain underlying a fluid domain using a two-domain approach. The impact of medium anisotropy and inhomogeneity on the stability of the fluid-porous system is analyzed through linear stability analysis and energy budget analysis. The results show that the mode of the system changes from unimodal (porous) to bimodal (both porous and fluid) with an increase in anisotropy or a decrease in inhomogeneity. Different modes and types of instability are identified based on various governing parameters. Secondary flow patterns are analyzed to validate the least stable mode and the prevailing instability in the system.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Engineering, Multidisciplinary
Daniel van Huyssteen, Felipe Lopez Rivarola, Guillermo Etse, Paul Steinmann
Summary: The virtual element method, an extension of the finite element method, allows for arbitrary polygonal/polyhedral element geometry. This paper presents novel approaches for computing isotropic and anisotropic mesh refinement indicators suitable for the virtual element method, and compares them for two-dimensional linear elasticity on structured meshes. The contribution of the consistency and stabilization terms of the VE matrix in the context of mesh adaptivity is also investigated. The results show that the combination of refinement procedures based on the displacement and strain fields achieves the best performance, and the stabilization term can enhance adaptive refinement procedures.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2022)
Article
Environmental Sciences
Yufei Wang, Daniel Fernandez-Garcia, Maarten W. Saaltink
Summary: Geological carbon sequestration is a mechanism to mitigate climate change by capturing and storing CO2 in deep geological formations. This study investigates the impact of heterogeneity and gravity factor on the dissolution efficiency of CO2 in saline formations. The results show that the migration and dissolution of CO2 are influenced by the interplay between heterogeneity and gravity, and the underestimation of dissolution efficiency is common in numerical models due to the inability to accurately represent heterogeneity.
WATER RESOURCES RESEARCH
(2022)
Review
Energy & Fuels
Patrick A. Eigbe, Olatunbosun O. Ajayi, Olabode T. Olakoyejo, Opeyemi L. Fadipe, Steven Efe, Adekunle O. Adelaja
Summary: This paper investigates the feasibility of CO2 storage in geological formations using 3-dimensional seismic and well data from the Niger Delta region. The study reviews theoretical and experimental studies on CO2 sequestration globally, including the Niger Delta, and identifies the high potential for CO2 sequestration in this region. The gaps identified from the review form the basis for future research on accurately estimating injection pressure, rate, and depth for CO2 sequestration.
Article
Geosciences, Multidisciplinary
Joachim Mathiesen, Gaute Linga, Marek Misztal, Francois Renard, Tanguy Le Borgne
Summary: Solute transport in multiphase flow through porous media plays a crucial role in natural systems and geoengineering applications. This study investigates dispersion in multiphase flows using highly resolved numerical simulations of immiscible two-phase flow. The results show that the activation and deactivation of different flow pathways under capillary forces accelerate solute spreading compared to single phase flow. The study establishes transport laws under dynamic multiphase flows and identifies the controlling factors for solute dispersion in porous media.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Mechanics
Chiyu Xie, Wenhai Lei, Matthew T. Balhoff, Moran Wang, Shiyi Chen
Summary: The use of dispersed polymer microspheres in controlling preferential flow has proven to be more efficient and cost-effective than traditional methods by inducing pressure fluctuations to smartly control the flow. This intelligent mechanism allows for better performance in efficiency and economic aspects, with potential applications in enhancing oil recovery and soil wetting techniques.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Computer Science, Interdisciplinary Applications
Jumanah Al Kubaisy, Pablo Salinas, Matthew D. Jackson
Summary: We propose a new hybrid pressure formulation for modeling multiphase flow and transport in highly heterogeneous porous media using the control volume finite element (CVFE) method. This formulation effectively captures sharp saturation changes at material interfaces by employing a discontinuous pressure approximation. The method divides the porous medium into sub-domains and applies a discontinuous approximation at the sub-domain boundaries while using a continuous approximation elsewhere.
JOURNAL OF COMPUTATIONAL PHYSICS
(2023)
Article
Mathematics, Applied
Vinicius L. S. Silva, Claire E. Heaney, Yaqi Li, Christopher C. Pain
Summary: We propose a new application of generative adversarial networks (GANs) for time prediction (PredGAN) and measurement assimilation (DA-PredGAN). GANs have recently gained attention for their ability to generate realistic-looking images. In this study, we explore how GANs can be used in computational modeling and data assimilation. We apply these methods to a compartmental model in epidemiology to simulate the spread of COVID-19 in an idealized town, and the results show accurate predictions and efficient assimilation of observed data.
JOURNAL OF SCIENTIFIC COMPUTING
(2023)
Article
Mathematics, Applied
Sibo Cheng, Jianhua Chen, Charitos Anastasiou, Panagiota Angeli, Omar K. K. Matar, Yi-Ke Guo, Christopher C. C. Pain, Rossella Arcucci
Summary: In this paper, a system is proposed that combines reduced-order surrogate models with a novel data assimilation technique to incorporate real-time observations from different physical spaces into high-dimensional dynamical systems. The system uses local smooth surrogate functions to link the encoded system variables and the current observations, enabling variational data assimilation at low computational cost. The proposed approach improves the efficiency provided by reduced-order modeling and the accuracy of data assimilation.
JOURNAL OF SCIENTIFIC COMPUTING
(2023)
Article
Nuclear Science & Technology
Akash Venkateshwaran, Mahendhar Kumar, M. B. Shyam Kumar, D. Davidson Jebaseelan, R. Sivakumar, Aniket Joshi, Christopher Pain
Summary: In-vessel melt retention is a crucial safety design in nuclear reactors to prevent radiation release during beyond-design basis accidents. This study analyzes the effects of forced convection cooling and natural convection cooling through simulating the COPRA experiment, and also examines the impact of varying reactor pressure vessel (RPV) geometry sizes. The results provide valuable insights for future severe accident experiments and the design of reactors.
PROGRESS IN NUCLEAR ENERGY
(2023)
Article
Public, Environmental & Occupational Health
Sida Chen, Zixue Tai, Jianping Liu
Summary: This study examined the factors influencing the dissemination of Tai Ji Quan (TJQ) to diverse practicing communities in China. The findings showed that individual and environmental factors play important roles in shaping personal decisions in TJQ engagement. The study highlights the need for an ecological approach to promote the spread of TJQ to the general population.
JOURNAL OF PHYSICAL ACTIVITY & HEALTH
(2023)
Article
Computer Science, Interdisciplinary Applications
Rossella Arcucci, Dunhui Xiao, Fangxin Fang, Ionel Michael Navon, Pin Wu, Christopher C. Pain, Yi-Ke Guo
Summary: Numerical simulations are widely used for predicting complex air flows and pollution transport. Non-Intrusive Reduced Order Model (NIROM) has been proven to be an efficient method for numerical forecasting. However, the reduced space of the model leads to uncertainties, and computational methodologies also contribute to uncertainty. Taking these uncertainties into account is crucial for the acceptance of numerical simulations.
COMPUTERS & FLUIDS
(2023)
Article
Green & Sustainable Science & Technology
D. Petrovskyy, C. Jacquemyn, S. Geiger, M. D. Jackson, J. D. Machado Silva, S. Judice, F. Rahman, M. Costa Sousa
Summary: Sketch-based interface and modelling is a rapid and intuitive approach to create 3D reservoir models for evaluating geological concepts and uncertainties. It improves the efficiency of reservoir modelling and simulation workflows by highlighting key uncertainties.
INTERNATIONAL JOURNAL OF GREENHOUSE GAS CONTROL
(2023)
Correction
Mathematics, Applied
Vinicius L. S. Silva, Claire E. Heaney, Yaqi Li, Christopher C. Pain
JOURNAL OF SCIENTIFIC COMPUTING
(2023)
Article
Engineering, Chemical
Paulina Quintanilla, Daniel Navia, Stephen J. Neethling, Pablo R. Brito-Parada
Summary: This paper presents the development of an economic model predictive control (E-MPC) strategy that utilizes a dynamic flotation model to improve the performance of froth flotation systems. By incorporating air recovery dynamics and concentrate grade dynamics, the E-MPC strategy achieved significant improvements in metallurgical recovery while maintaining the specified grade. The strategy also introduced a dynamic variable, air recovery, which offers great potential for performance improvement in existing flotation systems.
MINERALS ENGINEERING
(2023)
Article
Mechanics
Xiaofei Wu, Hisham Abubakar-Waziri, Fangxin Fang, Claire Dilliway, Pin Wu, Jinxi Li, Runming Yao, Pankaj Bhavsar, Prashant Kumar, Christopher C. Pain, Kian Fan Chung
Summary: We modeled the transmission of SARS-CoV-2 in an isolation room at the Royal Brompton Hospital in London, using an adaptive mesh computational fluid dynamics model. The model was based on data collected during the patient's stay and aimed to optimize the design layout of the isolation room, considering the location of the air extractor, filtration rates, bed location of the patient, and the health and safety of the staff working in the area.
Article
Respiratory System
Hisham Abubakar-Waziri, Gopinath Kalaiarasan, Rebecca Wawman, Faye Hobbs, Ian Adcock, Claire Dilliway, Fangxin Fang, Christopher Pain, Alexandra Porter, Pankaj K. Bhavsar, Emma Ransome, Vincent Savolainen, Prashant Kumar, Kian Fan Chung
Summary: During the easing of COVID-19 pandemic restrictions in London, SARS-CoV2 RNA was detected in the air of hospital waiting areas, wards, and London Underground train carriages. This suggests that airborne transmission may be an important mode of spread. Further research is needed to determine the transmission potential of SARS-CoV2 detected in the air.
BMJ OPEN RESPIRATORY RESEARCH
(2023)
Article
Chemistry, Physical
Harry Collini, Matthew D. Jackson
Summary: Despite the wide range of interest and applications, the controls on surface charge of crude oil in aqueous solution are not well understood. This study collates and reviews previous measurements of zeta potential on crude oil, compares and contrasts the results, and reports new measurements of zeta potential on crude oil wetting films and layers. The results show that the zeta potential depends on electrolyte pH and the concentration of divalent ions Ca2+ and Mg2+. Lower pH and higher concentration of these divalent ions lead to more positive zeta potential. The findings have important implications for engineering and industrial activities involving crude oil.
ADVANCES IN COLLOID AND INTERFACE SCIENCE
(2023)
Article
Engineering, Multidisciplinary
Toby R. F. Phillips, Claire E. Heaney, Boyang Chen, Andrew G. Buchan, Christopher C. Pain
Summary: This paper presents a new approach that uses AI software libraries as an alternative method for solving discretized partial differential equations (PDEs). The approach represents numerical discretizations from finite volume and finite element methods by pre-determining weights within a neural network. No training of the network is required as the weights are defined by the discretization scheme. The solutions obtained using this approach are identical to those obtained with standard codes often written in Fortran or C++, and can run on different computer architectures without modification.
INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING
(2023)
Article
Environmental Sciences
Meiling Cheng, Fangxin Fang, Ionel Michael Navon, Jie Zheng, Jiang Zhu, Christopher Pain
Summary: In this study, machine learning models were used to accurately predict the spatiotemporal ozone concentration in the Beijing-Tianjin-Hebei region from 2013 to 2018. The results showed that these models achieved better prediction performance under various meteorological conditions.
SCIENCE OF THE TOTAL ENVIRONMENT
(2023)
Article
Environmental Sciences
H. Woodward, A. Schroeder, A. de Nazelle, C. C. Pain, M. E. J. Stettler, H. ApSimon, A. Robins, P. F. Linden
Summary: The spatio-temporal variability of exposure to harmful pollutants in roadside areas is often neglected in assessments of pedestrian and cyclist exposures. This study aims to fully describe this variability and evaluate the benefits of high spatio-temporal resolution over high spatial resolution only. The study also compares high resolution vehicle emissions modeling to using a constant volume source. The findings highlight the impact of peak exposures and emphasize the importance of considering high resolution temporal air pollution variability for accurate characterization of pedestrian and cyclist exposures.
SCIENCE OF THE TOTAL ENVIRONMENT
(2023)
