Sökning: "Vortex model"

Visar resultat 1 - 5 av 131 avhandlingar innehållade orden Vortex model.

  1. 1. Fluid Mechanics of Vertical Axis Turbines : Simulations and Model Development

    Författare :Anders Goude; Olov Ågren; Carlos Simão Ferreira; Uppsala universitet; []
    Nyckelord :Wind power; Marine current power; Vertical axis turbine; Wind farm; Channel flow; Simulations; Vortex model; Streamtube model; Control system; Graphics processing unit; CUDA; Fast multipole method; Engineering Science with specialization in Science of Electricity; Teknisk fysik med inriktning mot elektricitetslära;

    Sammanfattning : Two computationally fast fluid mechanical models for vertical axis turbines are the streamtube and the vortex model. The streamtube model is the fastest, allowing three-dimensional modeling of the turbine, but lacks a proper time-dependent description of the flow through the turbine. LÄS MER

  3. 2. Vortex fluctuations in superconductors

    Författare :Peter Olsson; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Superconductor; Two dimensions; vortex; coulomb gas; XY model; Kosterlitz-Thouless transition; high-Tc.;

    Sammanfattning : The vortex fluctuations have proved to be responsible for the onset of dissipation in thin type-II superconducting Aims. There is also growing evidence that dissipation in high- temperature superconductors exhibits the same kind of two-dimensional (2D) behavior. LÄS MER

  4. 3. Wind turbine wakes : controland vortex shedding

    Författare :Davide Medici; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Wind Energy; Power Optimisation; Active Control; Yaw; Vortex; Mechanical energy engineering; Mekanisk energiteknik;

    Sammanfattning : Wind tunnel studies of the wake behind a model wind turbine have been made in order to get a better understanding of wake development as well as the possibility to predict the power output from downstream turbines working in the wake of an upstream one. Both two-component hot-wire anemometry as well as particle image velocimetry (PIV) have been used to map the flow field. LÄS MER

  5. 4. Analytical vortex solutions to Navier-Stokes equation

    Författare :Henrik Tryggeson; Mats Lyberg; Maarten Brons; Växjö universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; conical vortex; Navier-Stokes equation; analytical solution; 2-D vortices; turbulence; vortex ring; stretched vortex; coherent structures; Fluid mechanics; Strömningsmekanik;

    Sammanfattning : Fluid dynamics considers the physics of liquids and gases. This is a branch of classical physics and is totally based on Newton's laws of motion. Nevertheless, the equation of fluid motion, Navier-Stokes equation, becomes very complicated to solve even for very simple configurations. LÄS MER

  7. 5. On Turbulence Modelling for Bilge Vortices: A Test of Eight Models for Three Cases

    Författare :Urban Svennberg; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; wake; turbulence modelling; nonlinear eddy-viscosity model; bilge vortices; ship flow; jet; Navier-Stokes equation; two-equation model; Reynolds stress model; vortex;

    Sammanfattning : This work is a test, in three steps, of turbulence models for the calculation of the flow field around ships. Eight models ranging from k-e and k-w models to a Reynolds-stress model (RSM) are tested. LÄS MER