Search for dissertations about: "acoustic wave equation"

Showing result 16 - 20 of 28 swedish dissertations containing the words acoustic wave equation.

  2. 16. Rough Scatterers in Acoustics and Elastodynamics

    Author : Per-Åke Jansson; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; acoustic scattering; penny-shaped crack; rough surfaces; elastodynamic scattering; T matrix; null field approach;

    Abstract : The purpose of this thesis is to investigate the influence of roughness on wave scattering from finite-sized surfaces, in particular elastic wave scattering from cracks. Acoustic scattering from a sphere is considered using the null field approach. READ MORE

  4. 17. The material distribution method : analysis and acoustics applications

    Author : Fotios Kasolis; Martin Berggren; Volker Schulz; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Material distribution method; fictitious domain method; finite element method; Helmholtz equation; linear elasticity; shape optimization; topology optimization;

    Abstract : For the purpose of numerically simulating continuum mechanical structures, different types of material may be represented by the extreme values {,1}, where 0.... READ MORE

  5. 18. Iterative Methods for Solving the Cauchy Problem for the Helmholtz Equation

    Author : Lydie Mpinganzima; Vladimir Kozlov; Bengt Ove Turesson; Fredrik Berntsson; Daniel Lesnic; Linköpings universitet; []
    Keywords : ;

    Abstract : The inverse problem of reconstructing the acoustic, or electromagnetic, field from inexact measurements on a part of the boundary of a domain is important in applications, for instance for detecting the source of acoustic noise. The governing equation for the applications we consider is the Helmholtz equation. READ MORE

  6. 19. A high-order accurate, collocated boundary element method for wave propagation in layered media

    Author : Elena Sundkvist; Kurt Otto; Elisabeth Larsson; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Numerical Analysis; Numerisk analys;

    Abstract : The ultimate goal of this research is to construct a hybrid model for sound propagation in layered underwater environments with curved boundaries by employing a differential formulation for inhomogeneous layers and a boundary integral formulation for homogeneous layers. The discretization of the new hybrid model is a combination of a finite difference method for the Helmholtz equation for inhomogeneous media and a collocated boundary element method (BEM) for the integral equation for homogeneous media, while taking special care of the open boundaries and the common interface. READ MORE

  7. 20. Reliable hp finite element computations of scattering resonances in nano optics

    Author : Juan Carlos Araujo-Cabarcas; Christian Engström; David Cohen; Mats G. Larson; Jeffrey Ovall; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Scattering resonances; Helmholtz problems; pseudospectrum; Lippmann-Schwinger equation; finite element methods; nonlinear eigenvalue problems; spurious solutions;

    Abstract : Eigenfrequencies are commonly studied in wave propagation problems, as they are important in the analysis of closed cavities such as a microwave oven. For open systems, energy leaks into infinity and therefore scattering resonances are used instead of eigenfrequencies. READ MORE