Search for dissertations about: "laminar-turbulent transition"

Showing result 11 - 15 of 36 swedish dissertations containing the words laminar-turbulent transition.

2. 11. Analysis and control of transitional shear flows using global modes

   Author : Shervin Bagheri; Dan Henningson; Alessandro Bottaro; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Fluid mechanics; flow control; hydrodynamic stability; global modes; jet in crossflow; flat-plate boundary layer; laminar-turbulent transition; Arnoldi method; Koopman modes; balanced truncation; direct numerical simulations.; Fluid mechanics; Strömningsmekanik;

   Abstract : In this thesis direct numerical simulations are used to investigate two phenomenain shear flows: laminar-turbulent transition over a flat plate and periodicvortex shedding induced by a jet in cross flow. The emphasis is on understanding and controlling the flow dynamics using tools from dynamical systems and control theory. READ MORE

4. 12. Improvement of the nuclear safety code CATHARE based on thermal-hydraulic experiments for the Jules Horowitz Reactor

   Author : Alberto Ghione; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; nuclear research reactor; fully developed boiling; single-phase heat transfer; CATHARE; laminar-turbulent transition; narrow rectangular channels; JHR; single-phase friction; SULTAN-JHR;

   Abstract : The Jules Horowitz Reactor (JHR) is a material testing research reactor under construction at CEA-Cadarache (France). One of the computer codes employed in the safety analysis of this reactor is the thermal-hydraulic system code CATHARE. READ MORE

5. 13. Transitional and turbulent fibre suspension flows

   Author : Mathias Kvick; Fredrik Lundell; Daniel Söderberg; Lisa Prahl Wittberg; Björn Hof; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Fluid mechanics; fibre suspension; turbulence; laminar-turbulent transition; image analysis; hydrodynamic stability; cellulose nanofibrils.; Engineering Mechanics; Teknisk mekanik;

   Abstract : In this thesis the orientation of macro-sized fibres in turbulent flows is studied, as well as the effect of nano-sized fibrils on hydrodynamic stability. The focus lies on enabling processes for new materials where cellulose is the main constituent. READ MORE

6. 14. Flow control of boundary lagers and wakes

   Author : Jens H. M. Fransson; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Laminar-turbulent transition; asymptotic suction boundary layer; free stream turbulence; Tollmien-Schlichting wave; stability; flow control; cylinder wake; Engineering mechanics; Teknisk mekanik;

   Abstract : Both experimental and theoretical studies have beenconsidered on flat plate boundary layers as well as on wakesbehind porous cylinders. The main thread in this work iscontrol, which is applied passively and actively on boundarylayers in order to inhibit or postpone transition toturbulence; and actively through the cylinder surface in orderto effect the wakecharacteristics. READ MORE

7. 15. Study of generation, growth and breakdown of streamwise streaks in a Blasius boundary layer

   Author : Luca Brandt; KTH; []
   Keywords : Fluid mechanics; laminar-turbulent transition; boundary layer flow; transient growth; streamwise streaks; lift-up effect; receptivity; free-stream turbulence; streak instability; secondary instability; Direct Numerical Simulation.;

   Abstract : Transition from laminar to turbulent flow has beentraditionally studied in terms of exponentially growingeigensolutions to the linearized disturbance equations.However, experimental findings show that transition may occuralso for parameters combinations such that these eigensolutionsare damped. READ MORE