Search for dissertations about: "laminar-turbulent transition"

Showing result 21 - 25 of 36 swedish dissertations containing the words laminar-turbulent transition.

2. 21. Direct numerical simulation of turbulent flow in plane and cylindrical geometries

   Author : Jukka Komminaho; KTH; []
   Keywords : turbulence; plane Couette flow; pipe flow; laminar-turbulent transition; direct numerical simulation; spectral methods;

   Abstract : This thesis deals with numerical simulation of turbulentflows in geometrically simple cases. Both plane and cylindricalgeometries are used. The simplicity of the geometry allows theuse of spectral methods which yield a very high accuracy usingrelatively few grid points. A spectral method for planegeometries is implemented on a parallel computer. READ MORE

4. 22. Active Control and Reduced-Order Modeling of Transition in Shear Flows

   Author : Reza Dadfar; Dan S. Henningson; Ardeshir Hanifi; Shervin Bagheri; Vassilis Theofilis; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; SRA - E-Science SeRC ; SRA - E-vetenskap SeRC ;

   Abstract : In this thesis direct numerical simulation is used to investigate the possibilityto delay the transition from laminar to turbulent in boundary layer flows.Furthermore, modal analysis is used to reveal the coherent structures in highdimensional dynamical systems arising in the flow problems. READ MORE

5. 23. Flow control and reduced-order modelling of transition in shear flows

   Author : Reza Dadfar; Dan Henningson; Vasssilis Theofilis; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Flow control; plasma actuator; wing; leading edge; flat plate; wind turbine; optimal controller; model reduction; proper orthogonal decomposition; dynamic mode decomposition.;

   Abstract : In this thesis direct numerical simulation is used to investigate the possibility to delay the transition from a laminar to a turbulent flow in boundary layer flows. Furthermore, modal analysis techniques are used to identify the coherent structures in wind turbine wake. READ MORE

6. 24. Optimisation and control of shear flows

   Author : Antonios Monokrousos; Dan S. Henningson; Laurette Tuckerman; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; shear flows; flow control; optimal disturbances; Lagrange method; transition to turbulence; non-linear dynamics; Engineering mechanics; Teknisk mekanik;

   Abstract : Transition to turbulence and flow control are studied by means of numerical simulations for different simple shear flows. Linear and non-linear optimisation methods using the Lagrange multiplier technique are employed. READ MORE

7. 25. Oblique waves in boundary layer transition

   Author : Stellan Berlin; KTH; []
   Keywords : ;

   Abstract : Traditional research on laminar-turbulent transition has focused on scenarios that are caused by the exponential growth of eigensolutions to the linearized disturbance equations, e.g. two-dimensional Tollmien-Schlichting waves. READ MORE