Sökning: "Numerical acceleration"

Visar resultat 1 - 5 av 81 avhandlingar innehållade orden Numerical acceleration.

1. 1. Convergence Acceleration for Flow Problems

   Författare :Henrik Brandén; Sverker Holmgren; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Computational fluid dynamics; convergence acceleration; semicirculant preconditioning; fundamental solutions; Numerical Analysis; Numerisk analys;

   Sammanfattning : Convergence acceleration techniques for the iterative solution of system of equations arising in the discretisations of compressible flow problems governed by the steady state Euler or Navier-Stokes equations is considered. The system of PDE is discretised using a finite difference or finite volume method yielding a large sparse system of equations. LÄS MER

3. 2. Numerical study of flame dynamics

   Författare :Arkady Petchenko; Vitaly Bychkov; Leonid Kagan; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; combustion; Direct Numerical Simulation DNS ; turbulence; flame-vortex interaction; flame acceleration; flame-acoustic interaction; Physics; Fysik;

   Sammanfattning : Modern industrial society is based on combustion with ever increasing standards on the efficiency of burning. One of the main combustion characteristics is the burning rate, which is influenced by intrinsic flame instabilities, external turbulence and flame interaction with walls of combustor and sound waves. LÄS MER

4. 3. Turbulent burning, flame acceleration, explosion triggering

   Författare :V'yacheslav Akkerman; Vitaly Bychkov; Geoffrey Searby; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Turbulent combustion; flame acceleration; detonation explosion triggering; direct numerical simulations; Physics; Fysik;

   Sammanfattning : The present thesis considers several important problems of combustion theory, which are closely related to each other: turbulent burning, flame interaction with walls in different geometries, flame acceleration and detonation triggering. The theory of turbulent burning is developed within the renormalization approach. LÄS MER

5. 4. Extreme Electron Beams and Brilliant X-rays : Generation, Manipulation and Characterization of Relativistic Electron Beams for and from Plasma-Based Accelerators

   Författare :Jonas Björklund Svensson; Atomfysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; laser; plasma; wakefield; acceleration; accelerator; relativistic; electrons; x-rays; ultra-fast; betatron; laser-wakefield acceleration; plasma-wakefield acceleration; Fysicumarkivet A:2020:Björklund;

   Sammanfattning : This thesis is based on work done by the author on the development of plasma-based electron accelerators driven by ultra-intense laser pulses and dense electron bunches. Plasma based accelerators have several benefits, such as accelerating fields around 1000 times stronger than in “conventional” radio-frequency accelerators, which can allow for shrinking the overall footprint of the accelerator. LÄS MER

7. 5. Wind-induced vibrations in tall timber buildings : Design standards, experimental and numerical modal analyses

   Författare :Pierre Landel; Andreas Linderholt; Marie Johansson; Sigurdur Ormarsson; Petter Juell Nåvik; Linnéuniversitetet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Tall Timber Building; Wind-Induced vibration; Along-Wind Acceleration; Modal Analysis; Forced Vibration Test; Finite Element Model Reduction; Truss; Semi-Rigid Connection; Bâtiment en Bois de Grande Hauteur; Vibration Induite par le Vent; Accélération Parallèle au Vent; Analyse Modale; Test de Vibration Forcée; Réduction de Modèle aux Eléments finis; Poteau Treillis; Connexion Semi-Rigide; Hög Trähus; Vindinducerad Vibration; Acceleration Längs med Vinden; Modalanalys; Forcerat Vibrationstest; Finita Element Modellreduktion; Fackverk; Halvstyva Förband; Maskinteknik; Mechanical Engineering; Byggteknik; Civil engineering;

   Sammanfattning : Climate change and densification of cities are two major global challenges. Inthe building and construction industry, there are great expectations that tall timberbuildings will constitute one of the most sustainable solutions. First, verticalurban growth is energy and resource-efficient. LÄS MER