Sökning: "direct numerical simulations DNS"

Visar resultat 21 - 25 av 45 avhandlingar innehållade orden direct numerical simulations DNS.

  1. 21. Modelling and simulation of turbulence subject to system rotation

    Författare :Olof Grundestam; Arne Johansson; Sharath Girimaji; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Direct numerical simulations; least-squares method; turbulence model; nonlinear modelling; system rotation; streamline curvature; high-lift aerodynamics; Fluid mechanics; Strömningsmekanik;

    Sammanfattning : Simulation and modelling of turbulent flows under influence of streamline curvature and system rotation have been considered. Direct numerical simulations have been performed for fully developed rotating turbulent channel flow using a pseudo-spectral code. The rotation numbers considered are larger than unity. LÄS MER

  3. 22. Laminar and turbulent particle laden flows : a numerical and experimental study

    Författare :Seyed Hamid Tabaeikazerooni; Luca Brandt; Jeanette Hussong; Raffaella Ocone; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Suspension flow; inertial effect; turbulent duct flow; finite-size particles; Immersed Boundary Method IBM ; Astigmatism Particle Tracking Velocimetry APTV ; Engineering Mechanics; Teknisk mekanik;

    Sammanfattning : Particle laden flows are widespread in nature and in industrial applications. Dust storms, geophysical flows, pharmaceutical processes, fluidized beds and blood flow are only a few examples. Both global and local properties of a particle laden flow may alter significantly in comparison to the corresponding single phase flow. LÄS MER

  4. 23. Estimating the Air-Water Gas Transfer Velocity during Low Wind Conditions

    Författare :Sam Fredriksson; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Air.sea gas exchange; Turbulence; Heat flux; Natural convection; Shear; Direct numerical simulations; Gas transfer velocity; IR; Flux-chambers;

    Sammanfattning : The abundances of atmospheric carbon dioxide, CO2, and methane, CH4, are increasing. These increases affect e.g., the global carbon cycle and the climate both regionally and globally. LÄS MER

  5. 24. Direct Numerical Simulation of Boundary-layer Transition with Free-stream Turbulence

    Författare :Kristina Durovic; Dan Henningson; Ardeshir Hanifi; Philipp Schlatter; Tamer Zaki; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Engineering Mechanics; Teknisk mekanik;

    Sammanfattning : This thesis considers the generation and influence of free-stream turbulence toboundary layer transition on both flat and curved bodies in the flow. Variousflow configurations such as flow around the flat plate with a sharp leading edgeand low-pressure turbine blades are considered. LÄS MER

  7. 25. Topology optimization of transitional flows

    Författare :Harrison Nobis; Dan Henningson; Philipp Schlatter; Paolo Luchini; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Direct Numerical Simulation; Topology Optimization; Laminar– Turbulent Transition; Spectral Element Method; Direkt numerisk simulering; topologioptimering; laminär–turbulent omslag; spektralelementmetod; Teknisk mekanik; Engineering Mechanics;

    Sammanfattning : This thesis is concerned with the application of topology optimization in thedesign of structures that control fluids. A framework is developed in the high-order Spectral Element Method (SEM) code Nek5000, extending Nek5000 fromits original capabilities, performing Direct Numerical Simulations (DNS), toperforming density-based topology optimization. LÄS MER