Sökning: "symmetric hyperbolic system"

Visar resultat 1 - 5 av 7 avhandlingar innehållade orden symmetric hyperbolic system.

1. 1. On the Einstein-Vlasov system: Stationary Solutions and Small Data Solutions with Charged and Massless Particles

   Författare :Maximilian Thaller; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Static Solutions; Vector Field Method; non-linear wave equation; massless Einstein-Vlasov system; General Relativity; Conformal Einstein Field Equations; Minkowski stability; Vlasov matter; symmetric hyperbolic system; Einstein-Vlasov-Maxwell system;

   Sammanfattning : The Vlasov matter model describes an ensemble of collisionless particles moving through space-time. These particles interact via the gravitational field which they create collectively. In the framework of General Relativity this gravitational field is described by space-time curvature. LÄS MER

3. 2. Harmonic morphisms, Hermitian structures and symmetric spaces

   Författare :Martin Svensson; Matematik (naturvetenskapliga fakulteten); []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; isotropic subbundles; conformal foliations; holomorphic maps; harmonic morphism;

   Sammanfattning : A harmonic morphism is a map between two Riemannian manifolds with the property that its composition with a local harmonic function on the codomain is a local harmonic function on the domain. Such a map is automatically a harmonic map, satisfying an additional partial conformality condition called horizontal (weak) conformality. LÄS MER

4. 3. Towards higher order immersed finite elements for the wave equation

   Författare :Simon Sticko; Gunilla Kreiss; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Beräkningsvetenskap med inriktning mot numerisk analys; Scientific Computing with specialization in Numerical Analysis;

   Sammanfattning : We consider solving the scalar wave equation using immersed finite elements. Such a method might be useful, for instance, in scattering problems when the geometry of the domain is not known a priori. For hyperbolic problems, the amount of computational work per dispersion error is generally lower when using higher order methods. LÄS MER

5. 4. Stability, dual consistency and conservation of summation-by-parts formulations for multiphysics problems

   Författare :Fatemeh Ghasemi Zinatabadi; Jan Nordström; Thomas Hagstrom; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : In this thesis, we consider the numerical solution of initial boundary value problems (IBVPs). Boundary and interface conditions are derived such that the IBVP under consideration is well-posed. We also study the dual problem and the related dual boundary/interface conditions. LÄS MER

7. 5. Perfectly Matched Layers and High Order Difference Methods for Wave Equations

   Författare :Kenneth Duru; Gunilla Kreiss; Jan Nordsröm; Ken Mattsson; Marcus Grote; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Elastic waves; Surface waves; Perfectly matched layers; High order difference methods; Stability; Summation-by-parts operators; Boundary treatments; Beräkningsvetenskap med inriktning mot numerisk analys; Scientific Computing with specialization in Numerical Analysis;

   Sammanfattning : The perfectly matched layer (PML) is a novel technique to simulate the absorption of waves in unbounded domains. The underlying equations are often a system of second order hyperbolic partial differential equations. In the numerical treatment, second order systems are often rewritten and solved as first order systems. LÄS MER