Sökning: "wave operator"

Visar resultat 1 - 5 av 33 avhandlingar innehållade orden wave operator.

  1. 1. The Dirac Equation: Numerical and Asymptotic Analysis

    Författare :Hasan Almanasreh; Göteborgs universitet.; Gothenburg University.; [2012]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Dirac operator; eigenvalue problem; finite element method; spurious eigenvalues; Petrov-Galerkin; cubic Hermite basis functions; stability parameter; meshfree method; $hp$-cloud; intrinsic enrichment; G-convergence; $ Gamma$-convergence; scattering theory; identification; wave operator; stationary approach;

    Sammanfattning : The thesis consists of three parts, although each part belongs to a specific subject area in mathematics, they are considered as subfields of the perturbation theory. The main objective of the presented work is the study of the Dirac operator; the first part concerns the treatment of the spurious eigenvalues in the computation of the discrete spectrum. LÄS MER

  2. 2. Numerical Methods for Wave Propagation Analysis and Applications in Quantum Dynamics

    Detta är en avhandling från Uppsala : Acta Universitatis Upsaliensis

    Författare :Emil Kieri; Uppsala universitet.; Uppsala universitet.; [2016]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; computational wave propagation; quantum dynamics; time-dependent Schrödinger equation; spectral methods; Gaussian beams; splitting methods; low-rank approximation; Scientific Computing; Beräkningsvetenskap;

    Sammanfattning : We study numerical methods for time-dependent partial differential equations describing wave propagation, primarily applied to problems in quantum dynamics governed by the time-dependent Schrödinger equation (TDSE). We consider both methods for spatial approximation and for time stepping. LÄS MER

  3. 3. A Wave Expansion Method for Aeroacoustic Propagation

    Detta är en avhandling från KTH Royal Institute of Technology

    Författare :Johan Hammar; KTH.; [2016]
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Sound propagation; Sound generation; Aeroacoustics; Aerodynamics; Computational fluid dynamics; Computational aeroacoustics; Numerical methods; Lighthill; Curle; Ffowcs Williams and Hawkings; Frequency-domain propagation; Wave expansion method.; Farkostteknik; Vehicle and Maritime Engineering;

    Sammanfattning : Although it is possible to directly solve an entire flow-acoustics problem in one computation, this approach remains prohibitively large in terms of the computational resource required for most practical applications. Aeroacoustic problems are therefore usually split into two parts; one consisting of the source computation and one of the source propagation. LÄS MER

  4. 4. High Order Symmetric Finite Difference Schemes for the Acoustic Wave Equation

    Detta är en avhandling från Uppsala : Acta Universitatis Upsaliensis

    Författare :Abraham Zemui; Uppsala universitet.; Uppsala universitet.; [2003]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; finite element method; mass lumping; high order; finite difference method; wave equation; Numerical Analysis; Numerisk analys;

    Sammanfattning : When someone speaks, or when a piano is played, sound waves are spread through the room. Physically the propagation of sound is governed by the acoustic wave equation. This thesis deals with the problem of finding solutions to this equation by numerical methods. LÄS MER

  5. 5. Properties of wave-front sets and non-tangential convergence

    Detta är en avhandling från Växjö, Kalmar : Linnaeus University Press

    Författare :Karoline Johansson; Linnéuniversitetet.; [2011]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Fourier Banach spaces; Generalized free time-dependent Schrödinger equation; Micro-local; Modulation spaces; Non-tangential convergence; Pseudo-differential operators; Regularity; Wave-front sets.; MATHEMATICS Algebra; geometry and mathematical analysis Mathematical analysis; MATEMATIK Algebra; geometri och analys Analys; Matematik; Mathematics;

    Sammanfattning : In this thesis we consider regularity properties for solutions to partial differential equations and pseudo-differential equations. The thesis mainly concerns wave-front sets and micro-local properties. LÄS MER