Sökning: "Nonlinear wave equations"

Visar resultat 1 - 5 av 47 avhandlingar innehållade orden Nonlinear wave equations.

  1. 1. Geometric Methods for some Nonlinear Wave Equations

    Författare :Jonatan Lenells; Matematik (naturvetenskapliga fakulteten); []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Natural science; Geodesic flow; Nonlinear wave equations; Geometric methods; Naturvetenskap;

    Sammanfattning : A number of results related to the geometric interpretation of some dispersive nonlinear wave equations are presented. It is first described how some well-known shallow water equations arise geometrically as Euler equations for the geodesic flow on the Virasoro group endowed with certain right-invariant metrics. LÄS MER

  3. 2. Aspects of Wave Interaction in Nonlinear Media

    Författare :Björn Hall; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; nonlinear Schrödinger equation; incoherent solitons; partial incoherence; nonlinear wave interaction; Gross-Pitaevskii equation; modulational instability; collective dynamics; Wigner transform; nonlinear guided waves; Bose-Einstein condensation;

    Sammanfattning : Selected aspects of various types of nonlinear wave interaction are investigated. These aspects are studied in terms of models described by Nonlinear Schrödinger equations, mainly analytically and numerically, but also experimentally. LÄS MER

  4. 3. 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

  5. 4. Nonlinear interaction and propagation of gravitational and electromagnetic waves in plasmas

    Författare :Martin Servin; Gert Brodin; Lennart Stenflo; Demetrios Papadopoulos; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Theoretical physics; general relativity; plasma; gravitational waves; electromagnetic waves; nonlinear; wave interaction; wave propagation; Teoretisk fysik; Physics; Fysik; teoretisk fysik; Theoretical Physics;

    Sammanfattning : Gravitational waves and electromagnetic waves are important as carriers of energy and information. This thesis is devoted to the study of the propagation and interaction of these waves in plasmas, with emphasis on nonlinear effects and applications within astrophysics. LÄS MER

  7. 5. Transient waves in nonstationary media : with applications to lightning and nonlinear media

    Författare :Ingegerd Åberg; Institutionen för elektro- och informationsteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; lightning; Klein-Gordon; nonlinear; characteristics; wave splitting; imbedding; sources; propagators; Green functions; direct and inverse scattering; Nonstationary; transient; high-frequency switching; Kerr.; Technological sciences; Teknik;

    Sammanfattning : Propagation of transient waves in nonstationary, inhomogeneous, dispersive, stratified media is considered. Waves originating from sources exterior to the scatterer as well as from internal sources are treated. Algorithms are developed and illustrated by computations of wave phenomena in stationary, nonstationary and weakly nonlinear media. LÄS MER