Sökning: "Hybrid finite element difference method"

Visar resultat 1 - 5 av 14 avhandlingar innehållade orden Hybrid finite element difference method.

  1. 1. A hybrid finite element method for electromagnetics with applications in time-domain

    Författare :DAVID DEGERFELDT; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Nitsche s method; antenna arrays; NASA almond; edge elements; scattering; explicit-implicit time-stepping; Maxwell s equations; Finite Element Method; mass lumping; stability analysis; Finite-Differences Time-Domain; periodic structures; shape and material optimization;

    Sammanfattning : In this thesis, a new hybrid method that combines the Finite Element Method (FEM) with the Finite-Difference in Time-Domain (FDTD) method is presented. Tetrahedrons in the unstructured FEM region are connected directly to thehexahedrons in the structured FDTD region. LÄS MER

  3. 2. Stable FEM-FDTD Hybrid Method for Maxwell's Equations

    Författare :Thomas Rylander; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Finite Element Method; scattering; antennas; stability analysis; edge elements; Maxwell s equations; NASA almond; microwave circuits; mass lumping; proof of stability; explicit-implicit time-stepping; Finite-Differences Time-Domain;

    Sammanfattning : In this thesis edge elements are applied to solve several problems in computational electromagnetics. In particular, a hybrid scheme joining the Finite Element Method (FEM) and the Finite-Difference Time-Domain (FDTD) algorithm is developed, tested and exploited. LÄS MER

  4. 3. Optimization for scattering and radiation problems based on a stable FEM-FDTD hybrid method

    Författare :Tomas Halleröd; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; finite-difference time-domain; finite element method; array antennas; electric and magnetic losses; pattern synthesis; shape and material optimization; explicit-implicit time-stepping; scattering;

    Sammanfattning : In this thesis, a stable hybrid method combining the finite-elementmethod (FEM) and the finite-difference time-domain (FDTD) scheme forMaxwell's equations in two dimensions with both electric and magneticlosses is presented. It combines the flexibility of the FEM with theefficiency of the FDTD scheme. LÄS MER

  5. 4. Hybrid Solvers for the Maxwell Equations in Time-Domain

    Författare :Fredrik Edelvik; Per Lötstedt; Jan Hesthaven; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Maxwell s equations; time-domain; finite volume methods; finite element methods; hybrid solver; dispersive materials; thin wires; Beräkningsvetenskap; Scientific Computing;

    Sammanfattning : The most commonly used method for the time-domain Maxwell equations is the Finite-Difference Time-Domain method (FDTD). This is an explicit, second-order accurate method, which is used on a staggered Cartesian grid. The main drawback with the FDTD method is its inability to accurately model curved objects and small geometrical features. LÄS MER

  7. 5. Adaptive finite element/difference methods for time-dependent inverse scattering problems

    Författare :Larisa Beilina; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : In this thesis we develop adaptive hybrid finite element/difference methods for inverse time-domain acoustic and elastic scattering, where we seek to find the location and form of a (small) unknown object inside a large homogeneous body from measured wave-reflection data. We formulate the inverse problem as an optimal control problem, where we seek to reconstruct unknown material coefficients with best least squares wave fit to data. LÄS MER