Search for dissertations about: "linear stability"

Showing result 21 - 25 of 437 swedish dissertations containing the words linear stability.

  2. 21. Perfectly Matched Layers and High Order Difference Methods for Wave Equations

    Author : Kenneth Duru; Gunilla Kreiss; Jan Nordsröm; Ken Mattsson; Marcus Grote; Uppsala universitet; []
    Keywords : 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;

    Abstract : 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. READ MORE

  4. 22. Numerical studies of transtion in wall-bounded flows

    Author : Ori Levin; Dan Henningson; Nikolaus Adams; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; boundary layer; suction; wall jet; streaks; waves; periodic disturbance; localized disturbance; turbulent spot; algebraic growth; exponential growth; stability; transition thresholds; transition prediction; PSE; DNS; Fluid mechanics; Strömningsmekanik;

    Abstract : Disturbances introduced in wall-bounded flows can grow and lead to transition from laminar to turbulent flow. In order to reduce losses or enhance mixing in energy systems, a fundamental understanding of the flow stability and transition mechanism is important. READ MORE

  5. 23. Non-linear inverse geothermal problems

    Author : Dennis Wokiyi; Vladimir Kozlov; Fredrik Berntsson; Mårten Gulliksson; Linköpings universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES;

    Abstract : The inverse geothermal problem consist of estimating the temperature distribution below the earth’s surface using temperature and heat-flux measurements on the earth’s surface. The problem is important since temperature governs a variety of the geological processes including formation of magmas, minerals, fosil fuels and also deformation of rocks. READ MORE

  6. 24. Time Simulation of the Behaviour of Damaged Ships in Waves

    Author : Martin Schreuder; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; waves; SIMCAP; seakeeping; ship; damage; stability; dynamics;

    Abstract : The cause of event and ability for ship survival after damage are in many cases poorly described by pure static considerations. The dynamic properties of the ship and environment will be significant in the assessment of the damage scenario. Physical theories describing these properties have been developed since many decades. READ MORE

  7. 25. Hybrid Methods for Unsteady Fluid Flow Problems in Complex Geometries

    Author : Jing Gong; Jan Nordström; Gunilla Efraimsson; Mark H. Carpenter; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; hybrid methods; finite difference methods; finite volume methods; coupling procedure; stability; efficiency; artificial dissipation; Numerical analysis; Numerisk analys; Scientific Computing; Beräkningsvetenskap; Beräkningsvetenskap med inriktning mot numerisk analys;

    Abstract : In this thesis, stable and efficient hybrid methods which combine high order finite difference methods and unstructured finite volume methods for time-dependent initial boundary value problems have been developed. The hybrid methods make it possible to combine the efficiency of the finite difference method and the flexibility of the finite volume method. READ MORE