Sökning: "transition regime"

Visar resultat 11 - 15 av 158 avhandlingar innehållade orden transition regime.

1. 11. Attenuation of boundary layer disturbances by means of streamwise vortices

   Författare :Sohrab Sattarzadeh Shirvan; Jens H. M. Fransson; Valery Chernoray; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; boundary layer stability; Tollmien-Schlichting waves; oblique waves; transition to turbulence; streamwise vortices; miniature vortex generators; instability control; drag reduction;

   Sammanfattning : The stability of the boundary layer developed on a flat plate is studied in the presence of streamwise streaks where disturbances of different types are introduced in the wall-bounded shear layer. The experimental investigations are aimed at flow control by means of passively damping the energy growth of the disturbances in the streaky boundary layer and furthermore delay the onset of the transition in the streamwise direction. LÄS MER

3. 12. Stability and transition on wind turbine blades

   Författare :Thales Coelho Leite Fava; Ardeshir Hanifi; Dan Henningson; Stefania Cherubini; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Boundary layer stability; free-stream turbulence; laminar-turbulent transition; low-frequency oscillations; rotation effects; wind turbine blades.; Gränsskiktsstabilitet; friströmsturbulens; laminär-turbulent omslag; lågfrekventa svängningar; rotationseffekter; vindkraftverksblad.; Teknisk mekanik; Engineering Mechanics;

   Sammanfattning : Transition on wind turbine blades is a highly complex phenomenon due to the myriad effects influencing the process. This thesis studies some of them, namely free-stream turbulence (FST), rotation, and three-dimensionality. The investigations employ large eddy simulations (LES) with and without (implicit or wall-resolved LES) a subgrid-scale model. LÄS MER

4. 13. Nonlinear dynamics and smooth transition models

   Författare :Andrés González Gómez; Handelshögskolan i Stockholm; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : During the last few years nonlinear models have been a very active area of econometric research: new models have been introduced and existing ones generalized. To a large extent, these developments have concerned models in which the conditional moments are regime-dependent. LÄS MER

5. 14. Numerical studies of transtion in wall-bounded flows

   Författare :Ori Levin; Dan Henningson; Nikolaus Adams; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; boundary layer; suction; wall jet; streaks; waves; periodic disturbance; localized disturbance; turbulent spot; algebraic growth; exponential growth; stability; transition thresholds; transition prediction; PSE; DNS; Fluid mechanics; Strömningsmekanik;

   Sammanfattning : Disturbances introduced in wall-bounded flows can grow and lead to transition from laminar to turbulent flow. In order to reduce losses or enhance mixing in energy systems, a fundamental understanding of the flow stability and transition mechanism is important. LÄS MER

7. 15. 1809 : Statskuppen och regeringsformens tillkomst som tolkningsprocess

   Författare :Anders Sundin; Jan Lindegren; Max Edling; Mikael Alm; Jonas Nordin; Uppsala universitet; []
   Nyckelord :HUMANIORA; HUMANITIES; History; Sweden; 1809; instrument of government; constitution; political culture; political history; discourse analysis; conceptual history; constitutional change; public opinion; civic virtue; estate society; political representation; regime transition; Historia;

   Sammanfattning : This dissertation analyses the coup d’état and the instrument of government of 1809 as an interpretative framing process. By close examination primarily of official sources it focuses on how political actors utilized the components of the existing political culture in order to legitimise their actions. LÄS MER