Search for dissertations about: "Wave propagation problems"

Showing result 1 - 5 of 94 swedish dissertations containing the words Wave propagation problems.

  2. 1. Shape Optimization for Acoustic Wave Propagation Problems

    Author : Rajitha Udawalpola; Martin Berggren; Pekka Neittaanmäki; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; shape optimization; design optimization; acoustic wave propagation; Helmholtz equation; Boundary Element Method; Finite Element Method; inverse problems; adjoint method; gradient-based optimization; Scientific Computing; Beräkningsvetenskap;

    Abstract : Boundary shape optimization is a technique to search for an optimal shape by modifying the boundary of a device with a pre-specified topology. We consider boundary shape optimization of acoustic horns in loudspeakers and brass wind instruments. READ MORE

  4. 2. Wave Propagation in Structural Elements - Direct and Inverse Problems in the Time Domain

    Author : Peter Folkow; Chalmers tekniska högskola; []
    Keywords : 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;

    Abstract : 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. READ MORE

  5. 3. Finite Difference Methods for Time-Dependent Wave Propagation Problems

    Author : Ylva Ljungberg Rydin; Ken Mattsson; Erik Sjöqvist; Magnus Svärd; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Finite differences; Wave propagation problems; Summation-by-parts; Simultaneous approximation term; High-order accuracy; Deforming domains; Point sources; Scientific Computing; Beräkningsvetenskap;

    Abstract : Wave propagation models are essential in many fields of physics, such as acoustics, electromagnetics, and quantum mechanics. Mathematically, waves can be described by partial differential equations (PDEs).  In most cases, exact solutions to wave-dominated PDEs are nearly impossible to derive. READ MORE

  6. 4. Material distribution-based topology optimization for wave propagation problems

    Author : Ahmad Hasnain Bokhari; Eddie Wadbro; Martin Berggren; Roland Herzog; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; topology optimization; material distribution; wave propagation problems; Helmholtz equation; acoustics; electromagnetics; plasmonics;

    Abstract : This thesis employs material distribution-based topology optimization for wave propagation problems. In the material distribution approach, we define a material indicator function that models the presence and absence of material in a design domain. READ MORE

  7. 5. Numerical Methods for Wave Propagation : Analysis and Applications in Quantum Dynamics

    Author : Emil Kieri; Sverker Holmgren; Vasile Gradinaru; Hans O. Karlsson; Tobias Jahnke; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; computational wave propagation; quantum dynamics; time-dependent Schrödinger equation; spectral methods; Gaussian beams; splitting methods; low-rank approximation; Scientific Computing; Beräkningsvetenskap;

    Abstract : 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. READ MORE