Sökning: "High order difference methods"

Visar resultat 11 - 15 av 194 avhandlingar innehållade orden High order difference methods.

  1. 11. High Order Finite Difference Methods with Artificial Boundary Treatment in Quantum Dynamics

    Författare :Anna Nissen; Gunilla Kreiss; Sverker Holmgren; Magnus Svärd; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Schrödinger equation; finite difference methods; perfectly matched layer; summation-by-parts operators; adaptive discretization; stability; Beräkningsvetenskap med inriktning mot numerisk analys; Scientific Computing with specialization in Numerical Analysis;

    Sammanfattning : The investigation of the dynamics of chemical reactions, both from the theoretical and experimental side, has drawn an increasing interest since Ahmed H. Zewail was awarded the 1999 Nobel Prize in Chemistry for his work on femtochemistry. LÄS MER

  3. 12. High Order Local Radial Basis Function Methods for Atmospheric Flow Simulations

    Författare :Erik Lehto; Elisabeth Larsson; Natasha Flyer; Tobin Driscoll; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Radial basis function; meshless method; high order finite difference; atmospheric flow; hyper-viscosity; stable algorithm; Scientific Computing; Beräkningsvetenskap;

    Sammanfattning : Since the introduction of modern computers, numerical methods for atmospheric simulations have routinely been applied for weather prediction, and in the last fifty years, there has been a steady improvement in the accuracy of forecasts. Accurate numerical models of the atmosphere are also becoming more important as researchers rely on global climate simulations to assess and understand the impact of global warming. LÄS MER

  4. 13. Hybrid Methods for Unsteady Fluid Flow Problems in Complex Geometries

    Författare :Jing Gong; Jan Nordström; Gunilla Efraimsson; Mark H. Carpenter; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; hybrid methods; finite difference methods; finite volume methods; coupling procedure; stability; efficiency; artificial dissipation; Numerical analysis; Numerisk analys; Scientific Computing; Beräkningsvetenskap; Beräkningsvetenskap med inriktning mot numerisk analys;

    Sammanfattning : In this thesis, stable and efficient hybrid methods which combine high order finite difference methods and unstructured finite volume methods for time-dependent initial boundary value problems have been developed. The hybrid methods make it possible to combine the efficiency of the finite difference method and the flexibility of the finite volume method. LÄS MER

  5. 14. Uncertainty Quantification and Numerical Methods for Conservation Laws

    Författare :Per Pettersson; Jan Nordström; Gianluca Iaccarino; Gunilla Kreiss; Rémi Abgrall; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; uncertainty quantification; polynomial chaos; stochastic Galerkin methods; conservation laws; hyperbolic problems; finite difference methods; finite volume methods; Beräkningsvetenskap med inriktning mot numerisk analys; Scientific Computing with specialization in Numerical Analysis;

    Sammanfattning : Conservation laws with uncertain initial and boundary conditions are approximated using a generalized polynomial chaos expansion approach where the solution is represented as a generalized Fourier series of stochastic basis functions, e.g. orthogonal polynomials or wavelets. LÄS MER

  7. 15. Summation-by-Parts Finite Difference Methods for Wave Propagation and Earthquake Modeling

    Författare :Vidar Stiernström; Ken Mattsson; Mark H. Carpenter; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Finite difference method; high-order accuracy; stability; summation-by-parts; wave propagation; earthquake modeling; inverse problems; Beräkningsvetenskap med inriktning mot numerisk analys; Scientific Computing with specialization in Numerical Analysis;

    Sammanfattning : Waves manifest in many areas of physics, ranging from large-scale seismic waves in geophysics down to particle descriptions in quantum physics. Wave propagation may often be described mathematically by partial differential equations (PDE). Unfortunately, analytical solutions to PDEs are in many cases notoriously difficult to obtain. LÄS MER