Sökning: "surface boundary layers"

Visar resultat 1 - 5 av 89 avhandlingar innehållade orden surface boundary layers.

  1. 1. Studies of stratocumulus-topped boundary layers using a numerical weather prediction model

    Författare :Robert Sigg; Peter Duynkereke; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; meteorologi; Meteorology;

    Sammanfattning : Persistent stratocumulus clouds are commonly observed in many areas on Earth. In general, stratocumulus clouds cool the Earth-atmosphere system due to their influence on the radiation budget. It is therefore essential to describe such clouds accurately in climate and numerical weather prediction models. LÄS MER

  3. 2. Receptivity of crossflow-dominated boundary layers

    Författare :David Tempelmann; Ardeshir Hanifi; Dan Henningson; Anatoli Tumin; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Receptivity; three-dimensional boundary layers; optimal growth; adjoint solutions; swept wing;

    Sammanfattning : This thesis deals with receptivity mechanisms of three-dimensional, crossflow-dominated boundary layers. The receptivity of two model problems, a swept-flat-plate and a swept-wing boundary layer, is investigated by solving the parabolised stability equations (PSE) as well as by performing direct numerical simulations (DNS). LÄS MER

  4. 3. On Surface Characteristics and Microstructural Development of Soft Magnetic Composite Powder and Components

    Författare :Christos Oikonomou; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; X-ray photoelectron spectroscopy; compaction; annealing; X-ray diffraction; soft magnetic composites; high resolution scanning electron microscopy; surface layers; magnetic testing; powder metallurgy; depth profiling; electron backscatter diffraction; focused ion beam; thickness determination; energy dispersive X-ray spectroscopy; microstructure;

    Sammanfattning : Soft Magnetic Composite (SMC) products manufactured by traditional Powder Metallurgical (PM) techniques, are strong candidate materials for electromagnetic applications. Their advantages are based on cost and energy efficient production methods, shape complexity realization and uniquely uniform and isotropic three dimensional (3D) magnetic properties. LÄS MER

  5. 4. 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

  7. 5. Stability and Receptivity of Three-Dimensional Boundary Layers

    Författare :David Tempelmann; Dan Henningson; Stefan Hein; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Receptivity; stability; optimal growth; three-dimensional boundary layers; parabolised stability equations; adjoint PSE; crossflow instability; Fluid mechanics; Strömningsmekanik;

    Sammanfattning : The stability and the receptivity of three-dimensional flat plate boundary layers is studied employing parabolised stability equations. These allow for computationally efficient parametric studies. Two different sets of equations are used. LÄS MER