Sökning: "finite difference method"

Visar resultat 16 - 20 av 211 avhandlingar innehållade orden finite difference method.

  1. 16. Efficient time-domain modelling suitable for optimising thermoacoustic devices

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

    Sammanfattning : Thermoacoustic heat pumps use acoustic work to transfer heat from cold to hot temperatures. Such devices benefit from being environmentally friendly, robust and simple. However, in practice these devices have too low efficiency and power compared to their conventional counterparts. LÄS MER

  3. 17. Summation-by-Parts Operators for High Order Finite Difference Methods

    Författare :Ken Mattsson; Nordström Jan; Gunilla Kreiss; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Dinite difference methods; accuracy; stability; dissipation; Numerical analysis; Numerisk analys; Scientific Computing; Beräkningsvetenskap; Numerical Analysis;

    Sammanfattning : High order accurate finite difference methods for hyperbolic and parabolic initial boundary value problems (IBVPs) are considered. Particular focus is on time dependent wave propagating problems in complex domains. Typical applications are acoustic and electromagnetic wave propagation and fluid dynamics. LÄS MER

  4. 18. Efficiency factors for space heating system in buildings

    Författare :Christian Brembilla; Thomas Olofsson; Ronny Östin; Mohsen Soleimani-Mohseni; Bjørn Reidar Sørensen; Umeå universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Efficiency factors of space heating; hydronic panel radiator; hydronic floor heating; multilayer wall; numerical modelling; room control volume; decrement factor; time delay; heat conduction; heat convection; heat radiation; heat storage; thermal inertia; Euler solver; Newton-Raphson method; synthetic weather file; feedback and feed-forward control strategies; adaptive control; validation methodology; uncertainty bands; robustness of model predictions; thermostatic booth simulator; differential sensitivity analysis; transient model of panel radiator with multiple storage elements; active thermal mass; benchmark performance indicator; linear regression model; calibration through uncertainty bands; hybrid model of low-energy building: law driven data driven; outdoor temperature compensation heating curve; solar radiation model; finite difference method; heat equation;

    Sammanfattning : The thesis focuses on the efficiency of the space heating system. In particular, the efficiency factors measure the efficiency of thermal zone. The efficiency factors measures how the energy is used in a space heating. LÄS MER

  5. 19. Simulation of Electro-Optic Modulators by a Time-Domain Beam-Propagation Method

    Författare :Elin Solberg; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; time-domain beam-propagation method; finite element method; tensor products; computational electromagnetics; photonics; electro-optic modulators; finite element method;

    Sammanfattning : Electro-optic modulators (EOMs) are components which convert electric signals to optical ones. They are needed, e.g., at the transmitter end of fiber-optic communication systems and in time-stretch analog-to-digital converters. LÄS MER

  7. 20. Dispersion Engineering : Negative Refraction and Designed Surface Plasmons in Periodic Structures

    Författare :Zhichao Ruan; Min Qiu; Henri Benisty; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; photonic crystal; dispersion property; negative refraction; surface plasmon polariton; designed surface plasmon; negative index material; layer-KKR method; finite-difference time-domain method; plane wave method; subwavelength imaging; open cavity; enhanced transmission; slowing light; Photonics; Fotonik;

    Sammanfattning : The dispersion property of periodic structures is a hot research topic in the last decade. By exploiting dispersion properties, one can manipulate the propagation of electromagnetic waves, and produce effects that do not exist in conventional materials. LÄS MER