Sökning: "non-modal analysis"

Visar resultat 6 - 9 av 9 avhandlingar innehållade orden non-modal analysis.

  1. 6. Linear and non-linear dynamics of non-autonomous flows

    Författare :J. Simon Kern; Dan S. Henningson; Ardeshir Hanifi; Peter J. Schmid; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Time-dependent flows; linear stability; non-linear dynamics; Floquet analysis; optimally time-dependent modes; Teknisk mekanik; Engineering Mechanics;

    Sammanfattning : Fluid flows subject to time-dependent external forces or boundary conditions are ubiquitous in biology and technical applications. Whether one considers birds flying by flapping their wings or the gust response of wind turbines, the flow is non-autonomous. LÄS MER

  3. 7. 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. 8. 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

  5. 9. Numerical studies of bypass transition in the Blasius boundary layer

    Författare :Luca Brandt; KTH; []
    Nyckelord :Fluid Mechanics; laminar-turbulent transition; boundary layer flow; transient growth; streamwise streaks; secondary instability;

    Sammanfattning : Experimental findings show that transition from laminar toturbulent ow may occur also if the exponentially growingperturbations, eigensolutions to the linearised disturbanceequations, are damped. An alternative non-modal growthmechanism has been recently identi fied, also based on thelinear approximation. LÄS MER