Sökning: "proper orthogonal decomposition"

Visar resultat 31 - 35 av 49 avhandlingar innehållade orden proper orthogonal decomposition.

1. 31. 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. 32. On Error-Controlled Numerical Model Reduction for Linear Transient FE² Analysis

   Författare :Fredrik Ekre; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; computational homogenization; error estimation; model reduction;

   Sammanfattning : Multiscale modeling is of high interest in the engineering community due to its ability to capture the overall response, while still accounting for processes and structures on underlying fine scales. One standard approach to multiscale modeling is the so-called FE² procedure, where the classic constitutive relation is replaced by a boundary value problem on a Representative Volume Element (RVE) comprising the underlying microscale features. LÄS MER

4. 33. Slipstream and Flow Structures in the Near Wake of High-Speed Trains

   Författare :Tomas W. Muld; Gunilla Efraimsson; Dan S. Henningson; Chris Baker; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : Train transportation is a vital part of the transportation system of today. Asthe speed of the trains increase, the aerodynamic effects become more impor-tant. One aerodynamic effect that is of vital importance for passengers’ andtrack workers’ safety is slipstream, i.e. LÄS MER

5. 34. Computation and Analysis of EGR Mixing in Internal Combustion Engine Manifolds

   Författare :Alexander Sakowitz; Laszlo Fuchs; Angelo Onorati; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Turbulent Mixing; Large Eddy Simulation; URANS; Internal Combustion Engines; Intake Manifolds; T-junction; Exhaust Gas Recirculation;

   Sammanfattning : This thesis deals with turbulent mixing processes occurring in internal combustion engines, when applying exhaust gas recirculation (EGR). EGR is a very efficient way to reduce emissions of nitrogen oxides (NOx) in internal combustion engines. LÄS MER

7. 35. A Particle Image Velocimetry Study of Bubbly Gas-Liquid Flow

   Författare :Xiaoyun Tu; Livsmedelsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; turbulent dispersion; Food and drink technology; Livsmedelsteknik; turbulence; Rushton turbine; stirred tank; slip velocity; bubbly gas liquid two-phase flow; coherent structure; CCD camera; PIV; POD;

   Sammanfattning : The aim of this work is to build a framework that can be used for characterizing the bubbly gas liquid turbulent flow in the stirred bioreactor tank. To this end we have developed and modified techniques with which to measure the velocity of both dispersed gas and carrier liquid phases by the optical measurement technique, a 2-CCD camera Particle Image Velocimetry (PIV) system; and to characterize the turbulence by the wavelets tool, Proper Orthogonal Decomposition (POD). LÄS MER