Sökning: "confined flows"

Visar resultat 6 - 10 av 33 avhandlingar innehållade orden confined flows.

1. 6. Feedback control and modal structures in transitional shear flows

   Författare :Onofrio Semeraro; Dan S. Henningson; Mihailo Jovanoic; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; flow control; flat-plate boundary layer; laminar-turbulent transition; Other engineering mechanics; Övrig teknisk mekanik;

   Sammanfattning :   Two types of shear flows are investigated in this thesis; numerical simulations are performed for the analysis and control of the perturbation arising in a boundary layer over a flat plate, whereas PIV measurements are analysed for the investigation of a confined turbulent jet. Modal structures of the flows are identified: the aim is to understand the flow phenomena and to identify reduced-order models for the feedback control design. LÄS MER

3. 7. Experimental Studies of Complex Flows through Image-Based Techniques

   Författare :Gabriele Bellani; FredrIk Lundell; James Olsen; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Engineering mechanics; Teknisk mekanik;

   Sammanfattning : This thesis deals with the development of experimental techniques for the study of complex flows inspired to a large extent by the papermaking process. In particular one part of this thesis is devoted to the development of laboratory experiments based on index-of-refraction matching and imaging techniques to study the behavior of dilute and concentrated suspension of elongated particles. LÄS MER

4. 8. Active Control and Modal Structures in Transitional Shear Flows

   Författare :Onofrio Semeraro; Dan Henningson; Bernd Noack; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Flow control; flat-plate boundary layer; optimal controllers; model reduction; turbulent jet; POD; DMD; Koopman modes;

   Sammanfattning : Flow control of transitional shear flows is investigated by means of numerical simulations. The attenuation of three-dimensional wavepackets of Tollmien-Schlichting (TS) and streaks in the boundary layer is obtained using active control in combination with localised sensors and actuators distributed near the rigid wall. LÄS MER

5. 9. Utilization of Decomposition Techniques for Analyzing and Characterizing Flows

   Författare :Christian Carlsson; Strömningsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Decomposition techniques; Proper orthogonal decomposition; Dynamic mode decomposition; Extended dynamic mode decomposition; Swirl switching; Swirling flow; Low swirl burner; Fluid-structure interaction;

   Sammanfattning : This thesis presents the utilization of two different decomposition techniques, proper orthogonal decomposition (POD) and dynamic mode decomposition (DMD), for enhanced understanding of flow structures and their stability. The advantages of these techniques are shown for a range of flow situations, most of which are turbulent. LÄS MER

7. 10. Fluid Mechanics of Solid-Liquid Suspensions – An Experimental and Numerical Study

   Författare :Torbjörn Virdung; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; multiphase; soalescence; confined jet; computational fluid dynamics; stirred vessel; laser doppler velocimetry; particle image velocimetry; solid-liquid suspension; pitched blade; gas-liquid;

   Sammanfattning : Multiphase flows are common in many applications in chemical, mineral, biochemical and several other process industries. Examples of equipment in which multiphase flows are encountered are stirred vessels and multiphase jets, in which suspensions are agitated by an impeller in the former case and distributed through a nozzle in the latter. LÄS MER