Search for dissertations about: "Numerical integration"

Showing result 21 - 25 of 195 swedish dissertations containing the words Numerical integration.

2. 21. Direct numerical simulation of turbulent flow in plane and cylindrical geometries

   Author : Jukka Komminaho; KTH; []
   Keywords : turbulence; plane Couette flow; pipe flow; laminar-turbulent transition; direct numerical simulation; spectral methods;

   Abstract : This thesis deals with numerical simulation of turbulentflows in geometrically simple cases. Both plane and cylindricalgeometries are used. The simplicity of the geometry allows theuse of spectral methods which yield a very high accuracy usingrelatively few grid points. A spectral method for planegeometries is implemented on a parallel computer. READ MORE

4. 22. 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. 23. Mathematical modelling and methodology for cost optimization of variable renewable electricity integration

   Author : Caroline Granfeldt; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; cost optimization; variation management; variable renewable electricity; variable splitting; electricity system modelling; consensus algorithm; Lagrangian relaxation; wind power integration; long-term investment models;

   Abstract : The global production of electricity contributes significantly to the release of carbon dioxide emissions. Therefore, a transformation of the electricity system is of vital importance in order to restrict global warming. READ MORE

6. 24. Numerical Methods for Aeroacoustic Analysis of Turbomachinery

   Author : Daniel Lindblad; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Convective Ffowcs Williams - Hawkings Equation; Computational Aeroacoustics; Acoustic Analogy; Von Neumann Stability Analysis; Tonal Noise; CAA; Harmonic Balance Method; Counter Rotating Open Rotor;

   Abstract : Air transportation is today an integral part of many peoples life and it continuously grow to serve more of us in new and ingenious ways. There are however negative sides to this growth as well, such as increased noise around airports and more CO2 emissions, which must be addressed if aviation is to be part of a sustainable future. READ MORE

7. 25. Regional Geoid Determination Methods for the Era of Satellite Gravimetry : Numerical Investigations Using Synthetic Earth Gravity Models

   Author : Jonas Ågren; Lars E. Sjöberg; Zdenek Martince; KTH; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Earth sciences; geoid determination; GOCE; synthetic earth gravity models; kernel modification; downward continuation; Geovetenskap; Earth sciences; Geovetenskap;

   Abstract : It is the purpose of this thesis to investigate different regional geoid determination methods with respect to their feasibility for use with a future GOCE satellite-only Earth Gravity Model (EGM). This includes investigations of various techniques, which involve different approximations, as well as the expected accuracy. READ MORE