Browsing Bergen Open Research Archive by Author "Radu, Florin Adrian"
Now showing items 1-18 of 18
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Adaptive asynchronous time-stepping, stopping criteria, and a posteriori error estimates for fixed-stress iterative schemes for coupled poromechanics problems
Ahmed, Elyes; Nordbotten, Jan Martin; Radu, Florin Adrian (Journal article; Peer reviewed, 2020)In this paper we develop adaptive iterative coupling schemes for the Biot system modeling coupled poromechanics problems. We particularly consider the space–time formulation of the fixed-stress iterative scheme, in which ... -
A convergent mass conservative numerical scheme based on mixed finite elements for two-phase flow in porous media
Radu, Florin Adrian; Kumar, Kundan; Nordbotten, Jan Martin; Pop, Sorin Iuliu (Research report, 2017)In this work we present a mass conservative numerical scheme for two-phase flow in porous media. The model for flow consists on two fully coupled, non-linear equations: a degenerate parabolic equation and an elliptic ... -
Higher order space-time elements for a non-linear Biot model
Borregales Reveron, Manuel Antonio; Radu, Florin Adrian (Lecture Notes in Computational Science and Engineering ; 126, Conference object; Peer reviewed; Book, 2019)In this work, we consider a non-linear extension of the linear, quasi-static Biot’s model. Precisely, we assume that the volumetric strain and the fluid compressibility are non-linear functions. We propose a fully discrete ... -
Impact of time-dependent wettability alteration on the dynamics of capillary pressure
Kassa, Abay; Gasda, Sarah; Kumar, Kundan; Radu, Florin Adrian (Journal article; Peer reviewed, 2020)Wettability is a pore-scale property that has an important impact on capillarity, residual trapping, and hysteresis in porous media systems. In many applications, the wettability of the rock surface is assumed to be constant ... -
Implicit linearization scheme for nonstandard two-phase flow in porous media
Kassa, Abay; Kumar, Kundan; Gasda, Sarah; Radu, Florin Adrian (Journal article; Peer reviewed, 2021)In this article, we consider a nonlocal (in time) two‐phase flow model. The nonlocality is introduced through the wettability alteration induced dynamic capillary pressure function. We present a monotone fixed‐point iterative ... -
Iterative Linearisation Schemes for Doubly Degenerate Parabolic Equations
Both, Jakub; Kumar, Kundan; Nordbotten, Jan Martin; Pop, Iuliu Sorin; Radu, Florin Adrian (Conference object; Peer reviewed; Journal article, 2019)Mathematical models for flow and reactive transport in porous media often involve non-linear, degenerate parabolic equations. Their solutions have low regularity, and therefore lower order schemes are used for the numerical ... -
Iterative schemes for surfactant transport in porous media
Illiano, Davide; Pop, Iuliu Sorin; Radu, Florin Adrian (Journal article; Peer reviewed, 2021)In this work, we consider the transport of a surfactant in variably saturated porous media. The water flow is modelled by the Richards equations and it is fully coupled with the transport equation for the surfactant. Three ... -
Iterative solvers for Biot model under small and large deformation
Borregales Reveron, Manuel Antonio; Kumar, Kundan; Nordbotten, Jan Martin; Radu, Florin Adrian (Journal article; Peer reviewed, 2021)We consider L-scheme and Newton-based solvers for Biot model under large deformation. The mechanical deformation follows the Saint Venant-Kirchoff constitutive law. Furthermore, the fluid compressibility is assumed to be ... -
An iterative staggered scheme for phase field brittle fracture propagation with stabilizing parameters
Brun, Mats Kirkesæther; Wick, Thomas; Berre, Inga; Nordbotten, Jan Martin; Radu, Florin Adrian (Journal article; Peer reviewed, 2020)This paper concerns the analysis and implementation of a novel iterative staggered scheme for quasi-static brittle fracture propagation models, where the fracture evolution is tracked by a phase field variable. The model ... -
Mathematics and Medicine: How mathematics, modelling and simulations can lead to better diagnosis and treatments
Hanson, Erik Andreas; Hodneland, Erlend; Lorentzen, Rolf Johan; Nævdal, Geir; Nordbotten, Jan Martin; Sævareid, Ove; Zanna, Antonella (Lecture Notes in Computational Science and Engineering, Chapter; Peer reviewed; Journal article, 2019)Starting with the discovery of X-rays by Röntgen in 1895, the progress in medical imaging has been extraordinary and immensely beneficial to diagnosis and therapy. Parallel to the increase of imaging accuracy, there is the ... -
Microfluidic study of effects of flow velocity and nutrient concentration on biofilm accumulation and adhesive strength in the flowing and no-flowing microchannels
Liu, Na; Skauge, Tormod; Landa-Marbán, David; Hovland, Beate; Thorbjørnsen, Bente; Radu, Florin Adrian; Vik, Bartek Florczyk; Baumann, Thomas; Bødtker, Gunhild (Journal article; Peer reviewed, 2019)Biofilm accumulation in porous media can cause pore plugging and change many of the physical properties of porous media. Engineering bioplugging may have significant applications for many industrial processes, while improved ... -
Monolithic and splitting solution schemes for fully coupled quasi-static thermo-poroelasticity with nonlinear convective transport
Brun, Mats Kirkesæther; Ahmed, Elyes; Berre, Inga; Nordbotten, Jan Martin; Radu, Florin Adrian (Journal article; Peer reviewed, 2020)This paper concerns monolithic and splitting-based iterative procedures for the coupled nonlinear thermo-poroelasticity model problem. The thermo-poroelastic model problem we consider is formulated as a three-field system ... -
On the optimization of the fixed‐stress splitting for Biot's equations
Storvik, Erlend; Both, Jakub; Kumar, Kundan; Nordbotten, Jan Martin; Radu, Florin Adrian (Peer reviewed; Journal article, 2019)In this work, we are interested in efficiently solving the quasi‐static, linear Biot model for poroelasticity. We consider the fixed‐stress splitting scheme, which is a popular method for iteratively solving Biot's equations. ... -
A pore-scale model for permeable biofilm: Numerical simulations and laboratory experiments
Landa-Marban, David; Liu, Na; Pop, Iuliu Sorin; Kumar, Kundan; Pettersson, Per; Bødtker, Gunhild; Skauge, Tormod; Radu, Florin Adrian (Peer reviewed; Journal article, 2019)In this paper, we derive a pore-scale model for permeable biofilm formation in a two-dimensional pore. The pore is divided into two phases: water and biofilm. The biofilm is assumed to consist of four components: water, ... -
Robust iterative schemes for non-linear poromechanics
Borregales Reveron, Manuel Antonio; Radu, Florin Adrian; Kumar, Kundan; Nordbotten, Jan Martin (Peer reviewed; Journal article, 2018)We consider a non-linear extension of Biot’s model for poromechanics, wherein both the fluid flow and mechanical deformation are allowed to be non-linear. Specifically, we study the case when the volumetric stress and the ... -
Transport of polymer particles in oil–water flow in porous media: Enhancing oil recovery
Endo Kokubun, Max Akira; Radu, Florin Adrian; Keilegavlen, Eirik; Kumar, Kundan; Spildo, Kristine (Peer reviewed; Journal article, 2019)We study a heuristic, core-scale model for the transport of polymer particles in a two-phase (oil and water) porous medium. We are motivated by recent experimental observations which report increased oil recovery when ... -
Upscaling of the Coupling of Hydromechanical and Thermal Processes in a Quasi-static Poroelastic Medium
Brun, Mats Kirkesæther; Berre, Inga; Nordbotten, Jan Martin; Radu, Florin Adrian (Peer reviewed; Journal article, 2018-08)We undertake a formal derivation of a linear poro-thermo-elastic system within the framework of quasi-static deformation. This work is based upon the well-known derivation of the quasi-static poroelastic equations (also ... -
Well-posedness of the fully coupled quasi-static thermo-poroelastic equations with nonlinear convective transport
Brun, Mats Kirkesæther; Radu, Florin Adrian; Ahmed, Elyes; Nordbotten, Jan Martin (Peer reviewed; Journal article, 2019-03)This paper is concerned with the analysis of the quasi-static thermo-poroelastic model. This model is nonlinear and includes thermal effects compared to the classical quasi-static poroelastic model (also known as Biot's ...