Sökning: "Dan S. Henningson"

Visar resultat 16 - 20 av 24 avhandlingar innehållade orden Dan S. Henningson.

  1. 16. Slipstream and Flow Structures in the Near Wake of High-Speed Trains

    Författare :Tomas W. Muld; Gunilla Efraimsson; Dan S. Henningson; Chris Baker; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : Train transportation is a vital part of the transportation system of today. Asthe speed of the trains increase, the aerodynamic effects become more impor-tant. One aerodynamic effect that is of vital importance for passengers’ andtrack workers’ safety is slipstream, i.e. LÄS MER

  3. 17. On optimization of natural convection flows

    Författare :Clio Saglietti; Dan S. Henningson; Kurt Maute; KTH; []
    Nyckelord :Natural convection cooling; topology optimization; flow optimization; heat sink; conjugate heat transfer; differentially heated cavity; optimal initial disturbances; adjoint optimization;

    Sammanfattning : Two different techniques are presented for enhancing the thermal  performance of natural convection cooled heat sinks. The physics is  described by solving the conjugate heat transfer problem with a  spectral element method. The temperature distribution is computed in  two sub-domains, whose solution is then conjugated. LÄS MER

  4. 18. 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. 19. 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

  7. 20. Feedback control and modal structures in transitional shear flows

    Författare :Onofrio Semeraro; Dan S. Henningson; Mihailo Jovanoic; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; flow control; flat-plate boundary layer; laminar-turbulent transition; Other engineering mechanics; Övrig teknisk mekanik;

    Sammanfattning :   Two types of shear flows are investigated in this thesis; numerical simulations are performed for the analysis and control of the perturbation arising in a boundary layer over a flat plate, whereas PIV measurements are analysed for the investigation of a confined turbulent jet. Modal structures of the flows are identified: the aim is to understand the flow phenomena and to identify reduced-order models for the feedback control design. LÄS MER