Sökning: "tip-vortex breakdown"

Hittade 4 avhandlingar innehållade orden tip-vortex breakdown.

  1. 1. On the Aerodynamic Design of the Boxprop

    Författare :Alexandre Capitao Patrao; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; CFD; Open Rotors; Wake Analysis Method; Propeller Design; Propellers; CROR; Optimization; Tip vortex; Propfans;

    Sammanfattning : Economic factors and environmental awareness are driving the evolution of aircraft engines towards increasingly lower fuel consumption and emissions. The Counter-Rotating Open Rotor (CROR) is actively being researched around the world, promising a significantly increased propulsion efficiency relative to existing turbofans by employing two, unducted, counter-rotating propeller blade rows, thereby increasing the bypass ratio of the engine and decreasing nacelle drag. LÄS MER

  3. 2. Wakes behind wind turbines - Studies on tip vortex evolution and stability

    Författare :Ylva Odemark; Jens Fransson; Jens Madsen; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; wind power; aerodynamics; hot-wire anemometry; vortex dynamics;

    Sammanfattning : The increased fatigue loads and decreased power output of a wind turbine placed in the wake of another turbine is a well-known problem when building new wind power farms. In order to better estimate the total power output of a wind power farm, knowledge about the development and stability of wind turbine wakes is crucial. LÄS MER

  4. 3. Wind-turbine wakes - Effects of yaw, shear and turbine interaction

    Författare :Elektra Kleusberg; Dan Henningson; Philipp Schlatter; Stefan Ivanell; Johan Meyers; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; wind-turbine wakes; yaw; tip-vortex breakdown; shear; computational fluid dynamics; actuator-line method; spectral-element method; Vindturbinsvakar; girning; turbulent nedbrott hos spetsvirvlar; skjuvning; vakinteraktion; beräkningsströmningsdynamik; actuator line-metod; spektralelementmetod; Engineering Mechanics; Teknisk mekanik;

    Sammanfattning : The actuator-line method is used together with the incompressible Navier–Stokes equations to investigate the flow development behind wind turbines. Initial investigations focus on providing a thorough validation of the implementation in the spectral-element flow solver Nek5000 against existing numerical and experimental datasets. LÄS MER

  5. 4. Numerical study on instability and interaction of wind turbine wakes

    Författare :Sasan Sarmast; Dan. S. Henningson; Per-Åge Krogstad; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Wind turbine wakes; Stability; interaction; POD; DMD; Teknisk mekanik; Engineering Mechanics;

    Sammanfattning : Numerical simulations of the Navier-Stokes equations are conducted to achieve a better understanding of the behavior of wakes generated by the wind turbines. The simulations are performed by combining the in-house developed code EllipSys3D with the actuator line technique. LÄS MER