Search for dissertations about: "Boundary Layer Transition"

Showing result 1 - 5 of 105 swedish dissertations containing the words Boundary Layer Transition.

  2. 1. Optimal Control of Boundary Layer Transition

    Author : Markus Högberg; KTH; []
    Keywords : laminar-turbulent transition; transition control; turbulence control; flow control; boundary layer flow; channel flow; optimal control; adjoint equations; Riccati equations; Orr--Sommerfeld--Squire equations; secondary instability; transient gro;

    Abstract : .... READ MORE

  4. 2. Edge states and transition to turbulence in boundary layers

    Author : Taras Khapko; Dan Henningson; Philipp Schlatter; Yohann Duguet; Rich Kerswell; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; boundary layer; transition to turbulence; direct numerical simulation; edge state; free-stream turbulence; bypass transition; probabilistic cellular automaton; turbulence at the onset; laminar–turbulent coexistence; laminarisation; Engineering Mechanics; Teknisk mekanik;

    Abstract : The focus of this thesis is the numerical study of subcritical transition to turbulence in boundary-layer flows. For the most part, boundary layers with uniform suction are considered. Constant homogeneous suction counteracts the spatial growth of the boundary layer, rendering the flow parallel. READ MORE

  5. 3. Receptivity of Boundary-Layer Flows over Flat and Curved Walls

    Author : Lars-Uve Schrader; Luca Brandt; Dan Stefan Henningson; Gregoire Casalis; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Boundary-layer receptivity; laminar-turbulent transition; swept-plate boundary layer; Görtler flow; leading-edge effects; swept-wing flow; crossflow vortices; Görtler rolls; disturbance streaks; wall roughness; free-stream turbulence; Fluid mechanics; Strömningsmekanik;

    Abstract : Direct numerical simulations of the receptivity and instability of boundary layers on flat and curved surfaces are herein reported. Various flow models are considered with the aim to capture aspects of flows over straight and swept wings such as wall curvature, pressure variations, leading-edge effects, streamline curvature and crossflow. READ MORE

  6. 4. Transition to turbulence in the asymptotic suction boundary layer

    Author : Taras Khapko; Dan Henningson; Philipp Schlatter; Yohann Duguet; Marc Avila; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; boundary layers; instability; laminar-turbulent transition; dynamical systems; edge states; near-wall turbulence; laminarisation;

    Abstract : The focus of this thesis is on the numerical study of subcritical transition to turbulence in the asymptotic suction boundary layer (ASBL). Applying constant homogeneous suction prevents the spatial growth of the boundary layer, granting access to the asymptotic dynamics. READ MORE

  7. 5. Transition delay in boundary-layer flows via reactive control

    Author : Nicolò Fabbiane; Dan S. Henningson; Shervin Bagheri; Denis Sipp; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; flow control; drag reduction; net energy saving; adaptive control; model-based control; optimal control; flat-plate boundary layer; laminar-to- turbulent transition; plasma actuator; direct numerical simulation; in-flight experiments; strömningsstyrning; friktionsreduktion; netto energibesparing; adaptiv styrning; modellbaserad styrning; optimal kontroll; gränsskikt öve en plan platta; laminärt till turbulent omslag; plasma aktuator; DNS; flyg prov; Engineering Mechanics; Teknisk mekanik;

    Abstract : Transition delay in boundary-layer flows is achieved via reactive control of flow instabilities, i.e. Tollmien-Schlichting (TS) waves. Adaptive and model-based control techniques are investigated by means of direct numerical simulations (DNS) and experiments. READ MORE