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Showing result 1 - 5 of 28 swedish dissertations matching the above criteria.

2. 1. Utilization of Decomposition Techniques for Analyzing and Characterizing Flows

   Author : Christian Carlsson; Strömningsteknik; []
   Keywords : 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;

   Abstract : 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. READ MORE

4. 2. Modal Decomposition of Separated Nozzle Flow

   Author : Ragnar Larusson; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Arnoldi; axisymmetric convergent-divergent nozzle; Mode Decomposision; Flow Separation; Resonance.; Dynamic Mode Decomposision; Computational Fluid Dynamics;

   Abstract : The applicability of two different eigenvalue algorithms coupled with an axisymmetric RANS solver to predict the eigenmodes of separated supersonic flow inside an axisymmetric convergent-divergent nozzle was investigated. These are the Arnoldi and the Dynamic Mode Decomposition (DMD) algorithms, respectively. READ MORE

5. 3. Flow control and reduced-order modelling of transition in shear flows

   Author : Reza Dadfar; Dan Henningson; Vasssilis Theofilis; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Flow control; plasma actuator; wing; leading edge; flat plate; wind turbine; optimal controller; model reduction; proper orthogonal decomposition; dynamic mode decomposition.;

   Abstract : In this thesis direct numerical simulation is used to investigate the possibility to delay the transition from a laminar to a turbulent flow in boundary layer flows. Furthermore, modal analysis techniques are used to identify the coherent structures in wind turbine wake. READ MORE

6. 4. Modal Analysis of Supersonic Flow Separation in Nozzles

   Author : Ragnar Larusson; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Separated Nozzle Flow; Dynamic Mode Decomposition; Hybrid RANSLES; CFD; Modal Analysis; Arnoldi;

   Abstract : Operating a convergent-divergent nozzle under overexpanded conditions can lead to supersonic flow separation in the divergent section of the nozzle. In this case, an attached oblique shock wave forms at the separation base. READ MORE

7. 5. Analysis of Flow Structures in Wake Flows for Train Aerodynamics

   Author : Tomas W. Muld; Dan Henningson; Gunilla Efraimsson; Shia-Hui Peng; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Train Aerodynamics; Slipstream; Wake Flow; Detached-EddySimulation; Proper Orthogonal Decomposition; Koopman Mode Decomposi-tion; Surface-mounted Cube; Aerodynamic Train Model; Fluid mechanics; Strömningsmekanik; Vehicle engineering; Farkostteknik;

   Abstract : Train transportation is a vital part of the transportation system of today anddue to its safe and environmental friendly concept it will be even more impor-tant in the future. The speeds of trains have increased continuously and withhigher speeds the aerodynamic effects become even more important. READ MORE