Sökning: "laminar-to- turbulent transition"

Visar resultat 11 - 15 av 21 avhandlingar innehållade orden laminar-to- turbulent transition.

1. 11. Oblique waves in boundary layer transition

   Författare :Stellan Berlin; KTH; []
   Nyckelord :;

   Sammanfattning : 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. LÄS MER

3. 12. Stability and transition in pitching wings

   Författare :Prabal Negi; Dan Henningson; Ardeshir Hanifi; Philipp Schlatter; Olivier Marquet; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Flyg- och rymdteknik; Aerospace Engineering; Vehicle and Maritime Engineering; Farkostteknik;

   Sammanfattning : The aeroelastic stability of airplanes is one of the most important aspects of airplane design. Flutter or divergence instabilities arising out of the interaction of fluid forces and structural elasticity must be avoided by design or through the limitation of the flight envelope. LÄS MER

4. 13. Transitional and turbulent flow in porous media

   Författare :Shervin Khayamyan; Carl-Erik Grip; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Strömningslära; Fluid Mechanics;

   Sammanfattning : Fluid flow through porous media takes place in many natural processes such as ground water flows, capillary flows in plants and flow in human organs and muscles. It is also of outmost importance to have knowledge of this flow in a number of industrial processes such as paper making, making of fibre boards, composites manufacturing, filtering, forming and sintering of iron ore pellets and drying and impregnation of wood. LÄS MER

5. 14. Study of generation, growth and breakdown of streamwise streaks in a Blasius boundary layer

   Författare :Luca Brandt; KTH; []
   Nyckelord :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.;

   Sammanfattning : 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. LÄS MER

7. 15. Adaptive and model-based control in laminar boundary-layer flows

   Författare :Nicolò Fabbiane; Dan S. Henningson; Aimee S. Morgans; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Flow control; Control theory; Optimal control; Adaptive control; Boundary-layer flow; Fluid dynamics; Plasma actuator; Surface hot-wire; Transition delay;

   Sammanfattning : In boundary-layer flows it is possible to reduce the friction drag by breaking the path from laminar to turbulent state. In low turbulence environments, the laminar-to-turbulent transition is dominated by local flow instabilities – Tollmien-Schlichting (TS) waves – that exponentially grows while being con- vected by the flow and, eventually, lead to transition. LÄS MER