Sökning: "finite-difference time-domain"

Visar resultat 6 - 10 av 56 avhandlingar innehållade orden finite-difference time-domain.

1. 6. Direct and Inverse Methods for Waveguides and Scattering Problems in the Time Domain

   Författare :Erik Abenius; Per Lötstedt; Mats Gustafsson; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Maxwell s equations; time-domain; FDTD; finite-element; hybrid; thin sheet; waveguide; PML; inverse scattering; adjoint; gradient-based; minimization; Beräkningsvetenskap med inriktning mot numerisk analys; Scientific Computing with specialization in Numerical Analysis;

   Sammanfattning : Numerical simulation is an important tool in understanding the electromagnetic field and how it interacts with the environment. Different topics for time-domain finite-difference (FDTD) and finite-element (FETD) methods for Maxwell's equations are treated in this thesis. LÄS MER

3. 7. Wave Propagation in Structural Elements - Direct and Inverse Problems in the Time Domain

   Författare :Peter Folkow; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; integro-differential equations; non-uniform beams; wave splitting; wave propagator; finite difference; Timoshenko beam; imbedding; Mindlin plate; inverse problem; viscoelastic damping; nonlinear rod; transient wave propagation; Green function;

   Sammanfattning : The subject of this thesis is direct and inverse wave propagation problems in structural elements. The considered structures are beams, plates and rods. The models for the beams and the plates are based on linear theory, while the rods are assumed to be nonlinear. The greater part of the work concerns the Timoshenko beam. LÄS MER

4. 8. Broadband Electromagnetic Scattering and Shielding Analysis using the Finite-Difference Time-Domain Method

   Författare :Torleif Martin; Anders Bondeson; Linköpings universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : This thesis deals with numerical simulations of Maxwell's equations using the Finite-Difference Time-Domain (FDTD) method. The method is widely used in scattering, antenna and electromagnetic compatibility (EMC) applications. LÄS MER

5. 9. Modified Stencils for Boundaries and Subgrid Scales in the Finite-Difference Time-Domain Method

   Författare :Jon Häggblad; Björn Engquist; Olof Runborg; Björn Sjögreen; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; FDTD; Yee; Staircasing;

   Sammanfattning : This thesis centers on modified stencils for the Finite-Difference Time-Domain method (FDTD), or Yee scheme, when modelling curved boundaries, obstacles and holes smaller than the discretization length.  The goal is to increase the accuracy while keeping the structure of the standard method, enabling improvements to existing implementations with minimal effort. LÄS MER

7. 10. 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