The Experts below are selected from a list of 718539 Experts worldwide ranked by ideXlab platform
Mary F Wheeler - One of the best experts on this subject based on the ideXlab platform.
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design of convergence criterion for fixed stress split iterative scheme for small strain anisotropic poroelastoplasticity coupled with single phase Flow
arXiv: Numerical Analysis, 2019Co-Authors: Saumik Dana, Mary F WheelerAbstract:We arrive at convergence criterion for the fixed stress split iterative scheme for single phase Flow coupled with small strain anisotropic poroelastoplasticity. The analysis is based on studying the equations satisfied by the difference of iterates to show that the iterative scheme is contractive. The contractivity is based on driving a term to as small a value as possible (ideally zero). This condition is rendered as the convergence criterion of the algorithm.
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adaptive numerical homogenization for upscaling single phase Flow and transport
Journal of Computational Physics, 2019Co-Authors: Yerlan Amanbek, Mary F Wheeler, Gurpreet Singh, Hans Van DuijnAbstract:Abstract We propose an adaptive multiscale method to improve the efficiency and the accuracy of numerical computations by combining numerical homogenization and domain decomposition for modeling Flow and transport. Our approach focuses on minimizing the use of fine scale properties associated with advection and diffusion/dispersion. Here a fine scale Flow and transport problem is solved in subdomains defined by a transient region where spatial changes in transported species concentrations are large while a coarse scale problem is solved in the remaining subdomains. Away from the transient region, effective macroscopic properties are obtained using local numerical homogenization. An Enhanced Velocity Mixed Finite Element Method (EVMFEM) as a domain decomposition scheme is used to couple these coarse and fine subdomains [1] . Specifically, homogenization is employed here only when coarse and fine scale problems can be decoupled to extract temporal invariants in the form of effective parameters. In this paper, a number of numerical tests are presented for demonstrating the capabilities of this adaptive numerical homogenization approach in upscaling Flow and transport in heterogeneous porous medium.
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a priori error analysis for transient problems using enhanced velocity approach in the discrete time setting
arXiv: Numerical Analysis, 2018Co-Authors: Yerlan Amanbek, Mary F WheelerAbstract:Time discretization along with space discretization is important in the numerical simulation of subsurface Flow applications for long run. In this paper, we derive theoretical convergence error estimates in discrete-time setting for transient problems with the Dirichlet boundary condition. Enhanced Velocity Mixed FEM as domain decomposition method is used in the space discretization and the backward Euler method and the Crank-Nicolson method are considered in the discrete-time setting. Enhanced Velocity scheme was used in the adaptive mesh refinement dealing with heterogeneous porous media [1, 2] for single phase Flow and transport and demonstrated as mass conservative and efficient method. Numerical tests validating the backward Euler theory are presented. This error estimates are useful in the determining of time step size and the space discretization size. References. [1] Yerlan Amanbek, Gurpreet Singh, Mary F Wheeler, and Hans van Duijn. Adaptive numerical homogenization for upscaling single phase Flow and transport. ICES Report,12:17, 2017. [2] Gurpreet Singh, Yerlan Amanbek, and Mary F Wheeler. Adaptive homogenization for upscaling heterogeneous porous medium. In SPE Annual Technical Conference and Exhibition. Society of Petroleum Engineers, 2017.
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an enhanced velocity multipoint flux mixed finite element method for darcy Flow on non matching hexahedral grids
International Conference on Conceptual Structures, 2015Co-Authors: Benjamin Ganis, Mary F Wheeler, Ivan YotovAbstract:Abstract This paper proposes a new enhanced velocity method to directly construct a flux-continuous velocity approximation with multipoint flux mixed finite element method on subdomains. This gives an efficient way to perform simulations on multiblock domains with non-matching hexa- hedral grids. We develop a reasonable assumption on geometry, discuss implementation issues, and give several numerical results with slightly compressible single phase Flow.
Xiaobing Li - One of the best experts on this subject based on the ideXlab platform.
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Cyclonic separation process intensification oil removal based on microbubble flotation
International journal of mining science and technology, 2013Co-Authors: Hongxiang Xu, Xiaobing LiAbstract:Abstract The cyclonic-static microbubble flotation column has dual effects including the cyclonic separation and floatation separation with the characteristics of the small lower limit of the effective separation size, short separation time, large handling capacity, and low operation cost. It shows significant advantages in the oily wastewater treatment field, especially the polymer flooding oily wastewater treatment aspect. In this paper, the cyclonic separation function mechanism of the cyclonic-static microbubble flotation column was studied, the impact of the parameters including the feeding rate, aeration rate, circulating pressure, and underFlow split ratio on the cyclonic separation efficiency was investigated, and the cyclonic separation efficiency model was established as well. In addition, by applying the Doppler Laser Velocimeter (LDV) and Fluent simulation software, the test and simulation to the Single-Phase Flow velocity field of the cyclonic separation section of the cyclonic-static microbubble flotation column were carried out, and the velocity distribution rule of the cyclonic separation section was analyzed under the Single-Phase Flow conditions.
Van Der John J Schaaf - One of the best experts on this subject based on the ideXlab platform.
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engineering model for single phase Flow in a multi stage rotor stator spinning disc reactor
Chemical Engineering Journal, 2014Co-Authors: De Mm Michiel Beer, J Jaap C Schouten, Joost J B Keurentjes, Van Der John J SchaafAbstract:An engineering model for Single-Phase Flow in a multi-stage rotor–stator spinning disc reactor is presented. The model is based on residence time distribution data, obtained by tracer injection experiments. Measurements are done for gap ratios of G = 0.017 and 0.03, rotational Reynolds numbers of Re = 4.4 × 104 to 2.05 × 106 and superposed dimensionless throughFlow rates of Cw = 127–421. A single rotor–stator cavity can be described by regions of radial plug Flow at low radial disc positions, in combination with a single ideally mixed region at high radial positions. The radial position where transition between plug Flow and ideally mixed regions occurs decreases with increasing rotational Reynolds number and gap ratio, and increases with increasing superposed throughFlow rate. The resulting Flow model is explained by the throughFlow and rotation dominated regions observed in rotor–stator cavities with superposed throughFlow. The model can be used to quantify performance characteristics of rotor–stator spinning disc reactors, without application of extensive numerical simulations. Results indicate that the model can be scaled up with any number of rotor–stator cavities in series, as well as with increasing disc radius and gap ratio. This makes it a valuable tool in scaling up production capacity of the spinning disc reactor.
Olaf Hinrichsen - One of the best experts on this subject based on the ideXlab platform.
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single phase Flow residence time distributions in a rotor stator spinning disc reactor
Chemical Engineering & Technology, 2016Co-Authors: Franz Haseidl, Peter Konig, Olaf HinrichsenAbstract:Residence time experiments are used to study the Single-Phase Flow hydrodynamics of a rotor-stator spinning disc reactor. Two reactor setups of different sizes are examined in order to identify the effects of the reactor’s operating parameters. In order to precisely determine the central moments of the reactors transfer functions, which allow conclusions on the fluid Flow profiles in the gap, a deconvolution procedure in time as well as in frequency domain is established. Different residence time models are compared with regard to their applicability for deconvolution and fitting. The spatial extensions of the convectionally backmixed and the plug Flow regions are quantified by means of a threshold method. Furthermore, the obtained results are incorporated into an engineering model and compared to literature.
Alexandru Tatomir - One of the best experts on this subject based on the ideXlab platform.
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verification benchmarks for single phase Flow in three dimensional fractured porous media
Advances in Water Resources, 2021Co-Authors: Inga Berre, Wietse M Boon, Bernd Flemisch, Alessio Fumagalli, Dennis Glaser, Eirik Keilegavlen, Anna Scotti, Ivar Stefansson, Alexandru TatomirAbstract:Abstract Flow in fractured porous media occurs in the earth’s subsurface, in biological tissues, and in man-made materials. Fractures have a dominating influence on Flow processes, and the last decade has seen an extensive development of models and numerical methods that explicitly account for their presence. To support these developments, four benchmark cases for Single-Phase Flow in three-dimensional fractured porous media are presented. The cases are specifically designed to test the methods’ capabilities in handling various complexities common to the geometrical structures of fracture networks. Based on an open call for participation, results obtained with 17 numerical methods were collected. This paper presents the underlying mathematical model, an overview of the features of the participating numerical methods, and their performance in solving the benchmark cases.
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verification benchmark for a single phase Flow hydro mechanical model comparison between comsol multiphysics and dumux
E3S Web of Conferences, 2020Co-Authors: Dejian Zhou, Alexandru Tatomir, Ingrid Tomac, Martin SauterAbstract:Numerical modelling of hydromechanical processes in geological environments has become an invaluable tool in understanding and predicting system behaviour. However, due to the different algorithms and numerical schemes implemented in the different models, model reliability may vary considerably. Modelling of single- and multi-phase Flow in porous media has been widely employed in various engineering applications such as geological disposal of nuclear waste, geological storage of carbon dioxide, high-temperature geothermal systems, or hydraulic fracturing for shale gas exploitation. Coupled hydro-mechanical (H-M) processes play a key role in the prediction of the behaviour of geological reservoirs during their development and testing operations. In this paper, we present a benchmark test on a Single-Phase Flow problem in a hydrogeological reservoir with 5 horizontal layers of different properties. The aim is to compare two hydromechanical (H-M) models that use a vertex-centred finite-volume discretization and a finite element discretization. The first model is constructed with the free-open source simulator DuMuX , and the second with the commercial software COMSOL Multiphysics. The verification study suggests general confidence in the model reliability, but also highlights and discusses several areas of discrepancies between two models.
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benchmarks for single phase Flow in fractured porous media
Advances in Water Resources, 2018Co-Authors: Bernd Flemisch, Inga Berre, Wietse M Boon, Alessio Fumagalli, Anna Scotti, Ivar Stefansson, Nicolas Schwenck, Alexandru TatomirAbstract:Abstract This paper presents several test cases intended to be benchmarks for numerical schemes for Single-Phase fluid Flow in fractured porous media. A number of solution strategies are compared, including a vertex and two cell-centred finite volume methods, a non-conforming embedded discrete fracture model, a primal and a dual extended finite element formulation, and a mortar discrete fracture model. The proposed benchmarks test the schemes by increasing the difficulties in terms of network geometry, e.g. intersecting fractures, and physical parameters, e.g. low and high fracture-matrix permeability ratio as well as heterogeneous fracture permeabilities. For each problem, the results presented are the number of unknowns, the approximation errors in the porous matrix and in the fractures with respect to a reference solution, and the sparsity and condition number of the discretized linear system. All data and meshes used in this study are publicly available for further comparisons.
