Sökning: "Per-Åge Krogstad"

Hittade 4 avhandlingar innehållade orden Per-Åge Krogstad.

  1. 1. Vortex generators and turbulent boundary layer separation control

    Författare :Ola Lögdberg; Henrik Alfredsson; Per-Åge Krogstad; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; turbulent boundary layer separation; adverse pressure gradient; vortex generators; control of separation; Fluid mechanics; Strömningsmekanik;

    Sammanfattning : Boundary layer separation is usually an unwanted phenomenon in most technical applications as for instance on airplane wings, on ground vehicles and in internal flows such as diffusers. If separation occurs it leads to loss of lift, higher drag and results in energy losses. LÄS MER

  3. 2. Wind-turbine wake flows - Effects of boundary layers and periodic disturbances

    Författare :Ylva Odemark; Jens Fransson; Per-Åge Krogstad; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; wind power; wind-turbine model; wind tunnel; porous disc; hot-wire anemometry; particle image velocimetry; blade element momentum method; large eddy simulations; actuator disc method;

    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 and a subject of intensive research. These problems are caused by the velocity gradients and high turbulence levels present in the wake of a turbine. LÄS MER

  4. 3. 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

  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; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Wind Turbines; CFD; EllipSys3D; Actuator Line; Stability; Wake; Vortex Model; SRA - E-Science SeRC ; SRA - E-vetenskap SeRC ;

    Sammanfattning : The optimization of new generation of the wind farms is dependent on our understanding of wind turbine wake development, wake dynamics and the interaction of the wakes. The overall goal of the optimization is decreasing the fatigue loading and increasing the power production of the wind farms. LÄS MER