Sökning: "Time discretizations"

Visar resultat 1 - 5 av 34 avhandlingar innehållade orden Time discretizations.

  1. 1. Discretizations of nonlinear dissipative evolution equations. Order and convergence

    Författare :Eskil Hansen; Numerisk analys; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; kontroll; systems; numerisk analys; control; Datalogi; numerical analysis; Computer science; B-convergence; Dissipative maps; Logarithmic Lipschitz constants; Galerkin methods; Nonlinear evolution equations; Time discretizations; system;

    Sammanfattning : The theme of this thesis is to study discretizations of nonlinear dissipative evolution equations, which arise in e.g. advection-diffusion-reaction processes. LÄS MER

  3. 2. Adaptive time-integration for goal-oriented and coupled problems

    Författare :Peter Meisrimel; Numerisk analys; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; time-adaptivity; goal-oriented problems; error estimation; coupled problems; waveform relaxation; asynchronous methods; conjugate heat transfer;

    Sammanfattning : We consider efficient methods for the partitioned time-integration of multiphysics problems, which commonly exhibit a multiscale behavior, requiring independent time-grids. Examples are fluid structure interaction in e.g., the simulation of blood-flow or cooling of rocket engines, or ocean-atmosphere-vegetation interaction. LÄS MER

  4. 3. Efficient Solvers for Space-Time Discontinuous Galerkin Spectral Element Methods

    Författare :Lea Miko Versbach; Numerisk analys; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Discontinuous Galerkin Method; Spectral Element Method; Finite Volume Method; Implicit Schemes; Preconditioner; Multigrid Method; Space-Time; Lobatto IIIC Method; Local Fourier Analysis;

    Sammanfattning : In this thesis we study efficient solvers for space-time discontinuous Galerkin spectral element methods (DG-SEM). These discretizations result in fully implicit schemes of variable order in both spatial and temporal directions. LÄS MER

  5. 4. High order summation-by-parts methods in time and space

    Författare :Tomas Lundquist; Jan Nordström; Peter Eliasson; David A. Kopriva; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; summation-by-parts; time integration; stiff problems; weak initial conditions; high order methods; simultaneous-approximation-term; finite difference; discontinuous Galerkin; spectral methods; conservation; energy stability; complex geometries; non-conforming grid interfaces; interpolation;

    Sammanfattning : This thesis develops the methodology for solving initial boundary value problems with the use of summation-by-parts discretizations. The combination of high orders of accuracy and a systematic approach to construct provably stable boundary and interface procedures makes this methodology especially suitable for scientific computations with high demands on efficiency and robustness. LÄS MER

  7. 5. Numerical approximations of time domain boundary integral equation for wave propagation

    Författare :Andreas Atle; KTH; []
    Nyckelord :MOT; Marching on in time; boundary integral equations;

    Sammanfattning : Boundary integral equation techniques are useful in thenumerical simulation of scattering problems for wave equations.Their advantage over methods based on partial di.erentialequations comes from the lack of phase errors in the wavepropagation and from the fact that only the boundary of thescattering object needs to be discretized. LÄS MER