Blar i NTNU Open på forfatter "Lie, Knut-Andreas"
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A fully implicit WENO scheme on stratigraphic and unstructured polyhedral grids
Lie, Knut-Andreas; Mykkeltvedt, Trine Solberg; Møyner, Olav (Journal article; Peer reviewed, 2019)Many authors have used higher-order spatial discretizations to reduce numerical diffusion, which can be particularly pronounced when simulating EOR processes involving active chemical substances that are transported by ... -
Accelerating multiscale simulation of complex geomodels by use of dynamically adapted basis functions
Klemetsdal, Øystein; Møyner, Olav; Lie, Knut-Andreas (Journal article; Peer reviewed, 2019)A number of different multiscale methods have been developed as a robust alternative to upscaling and as a means for accelerated reservoir simulation of high-resolution geomodels. In their basic setup, multiscale methods ... -
Applying hybrid methods to reduce nonphysical cycles in the flux field
Haugland, Christine Marie Øvrebø (Master thesis, 2012)In this thesis we present the theoretical background for the two-point flux-approximation method; (TPFA), mimetic discretisation methods, and the multipoint flux approximation method; (MPFA). Theoretical arguments concerning ... -
Automatic Differentiation in Julia with Applications to Numerical Solution of PDEs
Grøstad, Sindre (Master thesis, 2019)Denne masteroppgaven gir en introduksjon til automatisk derivasjon (AD) og hvordan det kan benyttes til å beregne den deriverte til hvilken som helst funksjon, med samme presisjon som et analytisk uttrykk, men uten å innføre ... -
Combining Gmsh and MRST - Developing software for more efficient grid creation in two dimensions
Berg, Andreas Bjelland (Bachelor thesis, 2022)Det kan være svært utfordrende å skape presise, nøyaktige grid-representasjoner av virkelige, kontinuerlige domener. Dette er spesielt sant når det kommer til modellering av geologiske formasjoner, ettersom de har en tendens ... -
Discontinuous Galerkin Methods with Optimal Ordering for Fast Reservoir Simulation on General Grids
Røe, Ola Iver (Master thesis, 2006)This thesis presents a fast solution strategy for a class of hyperbolic transport equations modelling flow in porous media. The basis of the strategy is discontinuous Galerkin schemes which combined with a numerical flux ... -
Divergence-free Isogeometric Methods for Flow in Porous Media
Birkevold, Jens (Master thesis, 2012)This thesis is focused on solving the Darcy flow problem using divergence-free isogeometric methods, and comparing these results to the ones obtained using traditional finite element methods with Taylor Hood elements. A ... -
Dynamic Coarsening and Local Reordered Nonlinear Solvers for Simulating Transport in Porous Media
Klemetsdal, Øystein Strengehagen; Lie, Knut-Andreas (Journal article; Peer reviewed, 2020)We present a robust and flexible sequential solution approach in which the flow equation is solved on the original grid, whereas the transport equations are solved with a new dynamic coarsening method that adapts the grid ... -
Efficient flow diagnostics proxies for polymer flooding
Krogstad, Stein; Lie, Knut-Andreas; Nilsen, Halvor Møll; Berg, Carl Fredrik; Kippe, Vegard (Journal article; Peer reviewed, 2017)Flow diagnostics refers to a family of numerical methods that within a few seconds can compute visually intuitive quantities illuminating flow patterns and well connections for full 3D reservoir models. The starting point ... -
Efficient reordered nonlinear Gauss–Seidel solvers with higher order for black-oil models
Klemetsdal, Øystein Strengehagen; Rasmussen, Atgeirr Flø; Møyner, Olav; Lie, Knut-Andreas (Journal article; Peer reviewed, 2019)The fully implicit method is the most commonly used approach to solve black-oil problems in reservoir simulation. The method requires repeated linearization of large nonlinear systems and produces ill-conditioned linear ... -
Efficient Solvers for Field-Scale Simulation of Flow and Transport in Porous Media
Klemetsdal, Øystein Strengehagen (Doctoral theses at NTNU;2019:374, Doctoral thesis, 2019)The first part of the thesis serves as an introduction to modelling of flow and transport in porous media from the perspective of reservoir simulation. We discuss generation of computational grids and discretization ... -
Fast estimation of pressure propagation on general grids
Halmøy, Cecilia Forshei (Master thesis, 2015)To optimize reservoir recovery, estimating drainage volume for different well scenarios to find optimal well locations, is crucial. Knowing the pressure propagation for different well scenarios we can use this to estimate ... -
Full Approximation Scheme for Reservoir Simulation
Toft, Raymond; Lie, Knut-Andreas; Møyner, Olav (Journal article; Peer reviewed, 2018)Simulation of multiphase flow and transport in porous rock formations give rise to large systems of strongly coupled nonlinear equations. Solving these equations is computationally challenging because of orders of magnitude ... -
Full implicit WENO scheme for two phase flow in reservoir simulation
Knudsen, Thea (Master thesis, 2014)This master thesis studies the use of essentially non-oscillatory schemes for the spatial discretization in a full implicit two-phase flow model used to solve flow and transport in porous media. The implicit model is based ... -
Graph-based methods for data-driven reservoir modeling
Devold, Ingvild Strømsheim (Master thesis, 2023)Datadrevne metoder innen reservoarmodellering inkluderer både fullt ut databaserte maskinlæringsmetoder og historietilpasning av tradisjonelle matematiske modeller. I denne oppgaven foreslår vi en type hybride, grafbaserte ... -
Grid Orientation Effects and Consistent Discretizations for Simulation of Geologic Carbon Storage: A Study of the SPE11 Benchmark
Holme, Kristian (Master thesis, 2024)Denne oppgaven utforsker hvordan forskjellige grid-typer og diskretiseringsmetoder påvirker simuleringen av geologisk lagring av karbondioksid i akviferer med kompleks geometri. Med utgangspunkt i SPE11, en benchmark-beskrivelse ... -
High-Order Schemes for the Shallow Water Equations on GPUs
Berglie, Espen Graff (Master thesis, 2013)In this thesis, well-balanced, central-upwind high-resolution methods of high order are developed for the two-dimensional shallow water equations, on the graphics processing unit (GPU). The methods are based on a fifth-order ... -
Improved Optimization Methods For Adjoint-Based Training Of Reduced-Order Models
Khuat, Duy Duc (Master thesis, 2022)Simulasjon av flerfasestrømninger i porøse medier er et viktig felt grunnet dets mange anvendelsesområder. Til tross for dette har beregningskostnadene ofte vært en begrensende faktor i bruken av numeriske metoder for å ... -
Inductive Bias And The Information Bottleneck Method
Landsverk, Marius Mario Cervera (Master thesis, 2021)Induktiv bias referer til forskjellige arkitekturvalg som gjøres når man designer modeller for dyp læring. Spesielt så handler det om hvilke antakelser som gjøres om inngangsdataen, noe som i sin tur påvirker arkitekturvalget. ... -
Investigating iterative solvers of Poisson-type equations discretized by the Two-Point Flux-Approximation scheme
Mona-Lena Norheim (Master thesis, 2019)I denne masteroppgaven ser vi på alternative iterative løsere til MATLABs innebygde direkte løser \texttt{mldivide} for Poisson-type problemer. Løserene er testet på to forskjellige modeller som er vanlig å bruke for ...