Sökning: "multiscale"

Visar resultat 11 - 15 av 182 avhandlingar innehållade ordet multiscale.

  1. 11. Adaptive variational multiscale methods

    Författare :Axel Målqvist; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; finite element method; Galerkin; duality; a posteriori error estimation; adaptivity; variational multiscale method; mixed formulation; multi-physics; oil reservoir simulation; finite element method;

    Sammanfattning : In this thesis we present a new adaptive multiscale method for solving elliptic partial differential equations. The method is based on numerical solution of decoupled local fine scale problems on patches. LÄS MER

  3. 12. Generalized finite element methods for time-dependent multiscale problems

    Författare :Per Ljung; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; localized orthogonal decomposition; multiscale; Strongly damped wave equation; parabolic equations.; finite element method;

    Sammanfattning : In this thesis we develop and analyze generalized finite element methods for time-dependent partial differential equations (PDEs). The focus lies on equa- tions with rapidly varying coefficients, for which the classical finite element method is insufficient, as it requires a mesh fine enough to resolve the data. LÄS MER

  4. 13. Multiscale Methods and Uncertainty Quantification

    Författare :Daniel Elfverson; Axel Målqvist; Frédéric Legoll; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; multiscale methods; finite element method; discontinuous Galerkin; Petrov-Galerkin; a priori; a posteriori; complex geometry; uncertainty quantification; multilevel Monte Carlo; failure probability; Beräkningsvetenskap med inriktning mot numerisk analys; Scientific Computing with specialization in Numerical Analysis;

    Sammanfattning : In this thesis we consider two great challenges in computer simulations of partial differential equations: multiscale data, varying over multiple scales in space and time, and data uncertainty, due to lack of or inexact measurements.We develop a multiscale method based on a coarse scale correction, using localized fine scale computations. LÄS MER

  5. 14. Multiscale modeling of dynamic recrystallization

    Författare :Ylva Mellbin; Hållfasthetslära; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Dynamic recrystallization; Crystal plasticity; Texture; Grain size strengthening; Vertex model; Nucleation; Particle pinning; Large deformations; Multiscale modeling; GPGPU;

    Sammanfattning : During thermomechanical processing of metals, changes occur in the microstructure of the material which affect its macroscopic properties. By understanding these transformations in the microstructure, it becomes possible to design the processes in a way which yields the desired properties in the finished product. LÄS MER

  7. 15. Analysis and Applications of Heterogeneous Multiscale Methods for Multiscale Partial Differential Equations

    Författare :Doghonay Arjmand; Olof Runborg; Marcus Grote; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Numerical homogenization; long time wave propagation; multiscale PDEs; Tillämpad matematik och beräkningsmatematik; Applied and Computational Mathematics;

    Sammanfattning : This thesis centers on the development and analysis of numerical multiscale methods for multiscale problems arising in steady heat conduction, heat transfer and wave propagation in heterogeneous media. In a multiscale problem several scales interact with each other to form a system which has variations over a wide range of scales. LÄS MER