Sökning: "finite-difference time-domain method FDTD"

Visar resultat 1 - 5 av 26 avhandlingar innehållade orden finite-difference time-domain method FDTD.

1. 1. Thermoacoustic refrigerators: Time-domain modelling and experimental setup

   Författare :Stig Kleiven; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; finite-difference time-domain; refrigerator; thermoacoustics; equivalent source method;

   Sammanfattning : Thermoacoustic refrigerators use acoustic waves to transfer heat. Although their benefits compared with their vapour-compression counterparts are environmental friendliness, robustness and simplicity, they are currently still less efficient than traditional vapour-compression refrigerators. LÄS MER

3. 2. 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

4. 3. 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

5. 4. 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

7. 5. Analysis of Industrial Microwave Ovens

   Författare :Magnus Sundberg; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; source model; heat transfer; moment method; finite difference time domain; TM applicator; GMT; edge diffraction; thermal simulation; MMP; FDTD; generalized multipole technique; cost function; MM; optimization; magnetron; simulated annealing; multiple multipole program; microwave heating; edge overheating; TE applicator; tunnel-oven; applicator;

   Sammanfattning : This thesis deals with the analysis and design of microwave ovens used in the food industry. Such analysis is desirable in order to optimize the performance of the ovens and to reduce the time and expenses of developing new or improved ovens. LÄS MER