Sökning: "Vertical Axis"

Visar resultat 1 - 5 av 69 avhandlingar innehållade orden Vertical Axis.

  1. 1. Vertical Axis Wind Turbines : Electrical System and Experimental Results

    Författare :Jon Kjellin; Hans Bernhoff; Mats Leijon; Jonny Hylander; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; VAWT; H-rotor; start-up; all-electric control; Power Coefficient; stall; tip speed ratio; Renewable energy; Measurement systems; PM-generator;

    Sammanfattning : The wind power research at the division of Electricity at Uppsala University is aimed towards increased understanding of vertical axis wind turbines. The considered type of wind turbine is an H-rotor with a directly driven synchronous generator operating at variable speed. LÄS MER

  3. 2. Vertical Axis Wind Turbines : Tower Dynamics and Noise

    Författare :Erik Möllerström; Jonny Hylander; Fredric Ottermo; Göran Sidén; Hans Bernhoff; Mats Åbom; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; VAWT; H-rotor; eigenfrequency; semi-guy-wired tower; noise emission; sound power level;

    Sammanfattning : Vertical axis wind turbines (VAWTs) have with time been outrivaled by the today common and economically feasible horizontal axis wind turbines (HAWTs). However, VAWTs have several advantages such as the possibility to put the drive train at ground level, lower noise emissions and better scaling behavior which still make them interesting for research. LÄS MER

  4. 3. 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

  5. 4. Aerodynamics of Vertical Axis Wind Turbines : Development of Simulation Tools and Experiments

    Författare :Eduard Dyachuk; Hans Bernhoff; Sandra Eriksson; Anders Goude; Mac Gaunaa; Uppsala universitet; []
    Nyckelord :wind power; vertical axis turbine; H-rotor; simulations; streamtube model; vortex model; dynamic stall; measurements; blade; force; Engineering Science with specialization in Science of Electricity; Teknisk fysik med inriktning mot elektricitetslära;

    Sammanfattning : This thesis combines measurements with the development of simulation tools for vertical axis wind turbines (VAWT). Numerical models of aerodynamic blade forces are developed and validated against experiments. The studies were made on VAWTs which were operated at open sites. LÄS MER

  7. 5. Aeroacoustic Prediction for Vertical Axis Wind Turbines

    Författare :Aya Aihara; Hans Bernhoff; Anders Goude; Mats Åbom; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; fluid; acoustics; noise; sound; wind energy; vertical axis wind turbine; aerodynamics; airfoil; simulations; CFD; LES;

    Sammanfattning : This thesis investigates the aerodynamic and aeroacoustic prediction of vertical axis wind turbines, using computational fluid dynamics simulations. Noise pollution from wind turbines is one of the disadvantages of wind energy, calling for strategies to reduce noise levels. LÄS MER