Avancerad sökning

Visar resultat 11 - 15 av 268 avhandlingar som matchar ovanstående sökkriterier.

1. 11. Secondary currents in groundwater

   Författare :Maria Engström; Bo Nordell; Anders Sellgren; Clifford Voss; Luleå tekniska universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Groundwater; Vattenteknik; Water Resources Engineering;

   Sammanfattning : The thesis concerns the small vertical water movements created by thermal convection and the Coriolis force acting on groundwater flows. These small flows are of importance to vertical transports of temperature, nutrients and contaminants that would not be spread in the way they are. LÄS MER

3. 12. Exkursioner i gymnasieskolan : Lärande, motivation och plats

   Författare :Helen Schmidinger; Anders S. Brandt; Lena Molin; Hans Olof Gottfridsson; Uppsala universitet; []
   Nyckelord :excursions; flow; preparations; place; upper secondary school pupils; Social and Economic Geography; Kulturgeografi;

   Sammanfattning : The present licentiate thesis comprises a review of Swedish and Anglo-Saxon literature on excursions and their history, followed by a study on three one-day excursions and two neighbourhood excursions, conducted by pupils at upper secondary school. The primary purpose of the thesis was to highlight the development of excursion procedures, aiming at increasing the interest of the pupils, improving their inner motivation, but also to develop the learning process. LÄS MER

4. 13. Numerical studies on flows with secondary motion

   Författare :Jacopo Canton; Philipp Schlatter; David Moxey; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; nonlinear dynamical systems; instability; bifurcation; flow control; skin-friction reduction; Engineering Mechanics; Teknisk mekanik;

   Sammanfattning : This work is concerned with the study of flow stability and turbulence control - two old but still open problems of fluid mechanics. The topics are distinct and are (currently) approached from different directions and with different strategies. LÄS MER

5. 14. Effects of free-stream turbulence and three-dimensional roughness on boundary layer transition

   Författare :Santhosh Babu Mamidala; Jens H. M. Fransson; Bengt E. G. Fallenius; Jonathan Morrison; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; boundary-layer transition; intermittency; free-stream turbulence; electret microphones; isolated roughness; sinuous instability; varicose instability; Engineering Mechanics; Teknisk mekanik;

   Sammanfattning : External disturbances such as free-stream turbulence (FST), and isolated three-dimensional roughness are strong disturbance sources to the laminar boundary layers (BLs), which can lead to a rapid transition to turbulence. The transition process eventuates to increase in skin-friction coefficient and heat transfer rate and hence, both of the aforementioned disturbance sources have practical importance. LÄS MER

7. 15. Studies of the rotating-disk boundary-layer flow

   Författare :Shintaro Imayama; Henrik Alfredsson; Rebecca Lingwood; Peter Thomas; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Fluid mechanics; laminar-turbulent transition; convective instability; absolute instability; secondary instability; hot-wire anemometry; Teknisk mekanik; Engineering Mechanics;

   Sammanfattning : The rotating-disk boundary layer is not only a simpler model for the study of cross-flow instability than swept-wing boundary layers but also a useful simplification of many industrial-flow applications where rotating configurations are present. For the rotating disk, it has been suggested that a local absolute instability, leading to a global instability, is responsible for the small variation in the observed laminar-turbulent transition Reynolds number however the exact nature of the transition is still not fully understood. LÄS MER