Sökning: "Boundary-layer receptivity"

Visar resultat 11 - 15 av 16 avhandlingar innehållade orden Boundary-layer receptivity.

  1. 11. Stability and Receptivity of Three-Dimensional Boundary Layers

    Författare :David Tempelmann; Dan Henningson; Stefan Hein; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Receptivity; stability; optimal growth; three-dimensional boundary layers; parabolised stability equations; adjoint PSE; crossflow instability; Fluid mechanics; Strömningsmekanik;

    Sammanfattning : The stability and the receptivity of three-dimensional flat plate boundary layers is studied employing parabolised stability equations. These allow for computationally efficient parametric studies. Two different sets of equations are used. LÄS MER

  3. 12. Receptivity, Stability and Sensitivity analysis of two- and three-dimensional flows

    Författare :Guillaume Chauvat; Ardeshir Hanifi; Dan S. Henningson; Ulrich Rist; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; boundary-layers; stability; receptivity; sensitivity; transition; mode decomposition; Engineering Mechanics; Teknisk mekanik;

    Sammanfattning : This work deals with various aspects of boundary-layer stability. Modal and non-modal approaches are first used in the study of the global stability of a jet in crossflow. LÄS MER

  4. 13. Stability and transition on wind turbine blades

    Författare :Thales Coelho Leite Fava; Ardeshir Hanifi; Dan Henningson; Stefania Cherubini; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Boundary layer stability; free-stream turbulence; laminar-turbulent transition; low-frequency oscillations; rotation effects; wind turbine blades.; Gränsskiktsstabilitet; friströmsturbulens; laminär-turbulent omslag; lågfrekventa svängningar; rotationseffekter; vindkraftverksblad.; Teknisk mekanik; Engineering Mechanics;

    Sammanfattning : Transition on wind turbine blades is a highly complex phenomenon due to the myriad effects influencing the process. This thesis studies some of them, namely free-stream turbulence (FST), rotation, and three-dimensionality. The investigations employ large eddy simulations (LES) with and without (implicit or wall-resolved LES) a subgrid-scale model. LÄS MER

  5. 14. Receptivity of Boundary Layers under Pressure Gradient

    Författare :Lars-Uve Schrader; Luca Brandt; Dan Henningson; Tamer Zaki; KTH; []
    Nyckelord :Leading-edge effects;

    Sammanfattning : Boundary-layer flow over bodies such as aircraft wings or turbine blades is characterized by a pressure gradient due to the curved surface of the body. The boundary layer may experience modal and non-modal instability, and the type of dominant instability depends on whether the body is swept with respect to the oncoming flow or not. LÄS MER

  7. 15. Numerical studies of receptivity, stability and transition of wing and turbine blade boundary layers

    Författare :Luca De Vincentiis; Ardeshir Hanifi; Dan S. Henningson; Stefania Cherubini; KTH; []
    Nyckelord :Teknisk mekanik; Engineering Mechanics;

    Sammanfattning : In the present thesis, receptivity, stability and laminar-turbulent transition of different boundary-layer flows are addressed and investigated by means of direct numerical simulations. In particular, flows over a wing and a low-pressure-turbine (LPT) blade have been the main focus. LÄS MER