Sökning: "rough coefficients"

Visar resultat 1 - 5 av 15 avhandlingar innehållade orden rough coefficients.

  1. 1. Numerical Methods for Darcy Flow Problems with Rough and Uncertain Data

    Författare :Fredrik Hellman; Axel Målqvist; Auli Niemi; Fritjof Fagerlund; Robert Scheichl; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; numerical homogenization; multiscale methods; rough coefficients; high contrast coefficients; mixed finite elements; cdf estimation; multilevel Monte Carlo methods; Darcy flow problems; Beräkningsvetenskap med inriktning mot numerisk analys; Scientific Computing with specialization in Numerical Analysis;

    Sammanfattning : We address two computational challenges for numerical simulations of Darcy flow problems: rough and uncertain data. The rapidly varying and possibly high contrast permeability coefficient for the pressure equation in Darcy flow problems generally leads to irregular solutions, which in turn make standard solution techniques perform poorly. LÄS MER

  2. 2. Homogenization of some problems in hydrodynamic lubrication involving rough boundaries

    Författare :John Fabricius; Guy Bayada; Luleå tekniska universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Mathematics; partial differential equations; calculus of variations; homogenization theory; tribology; hydrodynamic lubrication; thin film flows; Reynolds equation; surface roughness; Weyl decomposition; Matematik; Mathematics; Matematik;

    Sammanfattning : This thesis is devoted to the study of some homogenization problems with applications in lubrication theory. It consists of an introduction, five research papers (I–V) and a complementary appendix.Homogenization is a mathematical theory for studying differential equations with rapidly oscillating coefficients. LÄS MER

  3. 3. Modelling of Dynamic Contact - Exemplified on the Tyre/Road Interaction

    Författare :Krister Larsson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; tyre dynamics; rolling noise; rolling contact; dynamic contact; tyre road noise; tyre road interaction;

    Sammanfattning : Noise is a severe problem in modern society. Road traffic noise is a substantial contributor and the tyre/road interaction is the main noise source for normal driving conditions. Despite more than 30 years of research, there is a lack of quantitative tyre/road noise prediction models. LÄS MER

  4. 4. Spectral properties of elliptic operators in singular settings and applications

    Författare :Medet Nursultanov; Göteborgs universitet; []

    Sammanfattning : The present thesis is focused on the investigation of the spectral properties of the linear elliptic operators in the presence of singularities. It is divided into three chapters. In the first chapter, we consider geometric singularities. LÄS MER

  5. 5. Design and development of a microwave multifrequency polarimetric scatterometer for biosphere remote sensing

    Författare :Anders Stjernman; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Polarimetry; scatterometer; microwave remote sensing; calibration; network analyzer based; S-parameters; scattering matrix;

    Sammanfattning : Microwave radar and radiometer techniques are used to gather crucial information about the earth and its atmosphere. The ERS-1, JERS-1, RadarSAT and NASA’s Mission to Planet Earth projects are designed to study the changing global environment. In all these endeavors, the key instrument is the radar or scatterometer. LÄS MER