Sökning: "Computational geometry"

Visar resultat 31 - 35 av 283 avhandlingar innehållade orden Computational geometry.

  1. 31. Adjoint-based aerodynamic shape optimization

    Författare :Olivier Amoignon; Martin Berggren; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Numerical Analysis; Numerisk analys;

    Sammanfattning : An adjoint system of the Euler equations of gas dynamics is derived in order to solve aerodynamic shape optimization problems with gradient-based methods. The derivation is based on the fully discrete flow model and involves differentiation and transposition of the system of equations obtained by an unstructured and node-centered finite-volume discretization. LÄS MER

  3. 32. Finite Element Methods for Interface Problems

    Författare :David Samvin; Peter Hansbo; Kent Salomonsson; Jönköping University; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Finite Element Method; Interface; Embedded; CutFEM; Finita elementmetoden; Sprickor; CutFEM;

    Sammanfattning : This thesis focuses on computationally efficient methods for flow in fractured porous media. Two approaches are presented where the interface is embedded on the underlying finite element mesh. The methods allow for representation of the interface geometry from the underlying discretization and with discontinuities across the interface. LÄS MER

  4. 33. 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. 34. Numerical methods for wave propagation in solids containing faults and fluid-filled fractures

    Författare :Ossian O'Reilly; Jan Nordström; Per Lötstedt; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : This thesis develops numerical methods for the simulation of wave propagation in solids containing faults and fluid-filled fractures. These techniques have applications in earthquake hazard analysis, seismic imaging of reservoirs, and volcano seismology. A central component of this work is the coupling of mechanical systems. LÄS MER

  7. 35. Numerical methods for waveguide modelling

    Författare :Christer Johansson; Björn Engquist; Per Lötstedt; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Waveguide; finite element; hp-adaptivity; helmholtz; maxwell; Numerical analysis; Numerisk analys;

    Sammanfattning : Waveguides are used to transmit electromagnetic signals. Their geometry is typically long and slender. This particular shape can be used in the design of efficient computational methods. Only special modes are transmitted and eigenvalue and eigenvector analysis becomes important. LÄS MER