Search for dissertations about: "Koopman Mode Decomposition"

Found 4 swedish dissertations containing the words Koopman Mode Decomposition.

2. 1. 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

4. 2. Spectral-element simulations of turbulent wall-bounded flows including transition and separation

   Author : Johan Malm; Dan Henningson; Philipp Schlatter; Suad Jakirlic; KTH; []
   Keywords : spectral-element method; direct numerical simulation DNS ; large-eddy simulation LES ; turbulence; transition; over-integration; three-dimensional separation; massively parallel simulations; proper orthogonal decomposition POD ; Koopman modes; vorticity stretching; coherence; SRA - E-vetenskap SeRC ; SRA - E-Science SeRC ;

   Abstract : The spectral-element method (SEM) is used to study wall-bounded turbulent flowsin moderately complex geometries. The first part of the thesis is devoted to simulations of canonical flow cases, such as temporal K-type transitionand turbulent channel flow, to investigate general resolution requirements and computational efficiency of the numerical code nek5000. READ MORE

5. 3. Active Control and Modal Structures in Transitional Shear Flows

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

   Abstract : 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. READ MORE

6. 4. The Impact of Non-synchronous Generation on Power Systems Dynamics

   Author : Harold Chamorro; Mehrdad Ghandhari; Jonas Persson; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Abstract : Due to the increasing integration of Renewable Energy Sources (RES), and the installation of High Voltage Direct Current (HVDC) systems, more power is injected to the AC grid based on power electronic converters. This kind of power injection is called non-synchronous generation in this thesis. READ MORE