Search for dissertations about: "Alexander Bobylev"

Showing result 1 - 5 of 6 swedish dissertations containing the words Alexander Bobylev.

  2. 1. On Half-Space and Shock-Wave Problems for Discrete Velocity Models of the Boltzmann Equation

    Author : Niclas Bernhoff; Alexander Bobylev; Giuseppe Toscani; Karlstads universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Boltzmann equation; discrete velocity models; boundary value problems; shock waves; MATHEMATICS; MATEMATIK; Matematik; Mathematics;

    Abstract : We study some questions related to general discrete velocity (with arbitrarily number of velocities) models (DVMs) of the Boltzmann equation. In the case of plane stationary problems the typical DVM reduces to a dynamical system (system of ODEs). Properties of such systems are studied in the most general case. READ MORE

  4. 2. On the Einstein-Vlasov system

    Author : Mikael Fjällborg; Alexander Bobylev; Markus Kunze; Karlstads universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Einstein-Vlasov system; finite extension; monotone functions; MATHEMATICS; MATEMATIK; Matematik; Mathematics;

    Abstract : In this thesis we consider the Einstein-Vlasov system, which models a system of particles within the framework of general relativity, and where collisions between the particles are assumed to be sufficiently rare to be neglected. Here the particles are stars, galaxies or even clusters of galaxies, which interact by the gravitational field generated collectively by the particles. READ MORE

  5. 3. Some numerical and analytical methods for equations of wave propagation and kinetic theory

    Author : Eva Mossberg; Alexander Bobylev; Giovanni Russo; Karlstads universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; wave propagation; finite difference metods high order methods; Landau-Fokker-Planck equation; Monte-Carlo simulations; Boltzmann equation; hard sphere model; eigenvalue problem; MATHEMATICS; MATEMATIK; Matematik; Mathematics;

    Abstract : This thesis consists of two different parts, related to two different fields in mathematical physics: wave propagation and kinetic theory of gases. Various mathematical and computational problems for equations from these areas are treated. READ MORE

  6. 4. Classification of Normal Discrete Kinetic Models

    Author : Mirela Christina Vinerean; Alexander Bobylev; Mirela Vinerean-Bernhoff; Karlstads universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Kinetic theory; discrete kinetic velocity models; conservation laws; MATHEMATICS; MATEMATIK; Matematik; Mathematics;

    Abstract : “In many interesting papers on discrete velocity models (DVMs), authors postulate from the beginning that the finite velocity space with "good" properties is given and only after this step they study the Discrete Boltzmann Equation. Contrary to this approach, our aim is not to study the equation, but to discuss all possible choices of finite phase spaces (sets) satisfying this type of "good" restrictions. READ MORE

  7. 5. Discrete Kinetic Models and Conservation Laws

    Author : Mirela Cristina Vinerean; Alexander Bobylev; Giampiero Spiga; Karlstads universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Kinetic theory; discrete kinetic velocity models; conservation laws; MATHEMATICS; MATEMATIK; Matematik; Mathematics;

    Abstract : Classical kinetic theory of gases is based on the Boltzmann equation (BE) which describes the evolution of a system of particles undergoing collisions preserving mass, momentum and energy. Discretization methods have been developed on the idea of replacing the original BE by a finite set of nonlinear hyperbolic PDEs corresponding to the densities linked to a suitable finite set of velocities. READ MORE