Sökning: "Viscosity model"

Visar resultat 26 - 30 av 236 avhandlingar innehållade orden Viscosity model.

1. 26. Modelling of Turbulent Flow and Heat Transfer for Building Ventilation

   Författare :Peng Shia-Hui; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; large eddy simulation; turbulent buoyant convection; ventilation performance assessment; purging flow rate; SGS modelling; ventilation flow; stochastic Markov chain model; turbulence modelling; LRN k-w model; two-equation models; building ventilation; transfer probability; transition regime; modified SGS buoyancy model; energy backscatter;

   Sammanfattning : This thesis contributes to studies on the assessment of building ventilation performance and the development of turbulence models accounting for Low-Reynolds-number (LRN) effects and buoyant convection with heat transfer. Assessments of building ventilation performance are discussed with respect to indoor air distribution and passive contaminant dispersion. LÄS MER

3. 27. Modelling of stably-stratified, convective and transitional atmospheric boundary layers using the explicit algebraic Reynolds-stress model

   Författare :Velibor Zeli; Gert Brethouwer; Arne V. Johansson; Stefan Wallin; Bert Holtslag; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; atmospheric turbulence; convective atmosphere; Reynolds-stress model; stably-stratified atmosphere; transitional atmosphere; Engineering Mechanics; Teknisk mekanik;

   Sammanfattning : The atmospheric boundary layer (ABL) is in continuous turbulent motion. The heating and cooling of the Earth’s surface drives mechanic and thermodynamic processes in the ABL through enhancing and damping of atmospheric turbulence. The surface forcing has a profound effect on the diurnal cycle of temperature,wind and related variables in the ABL. LÄS MER

4. 28. Electronic and Vibrational Coherence in Photosynthetic and Model Systems

   Författare :Mirianas Chachisvilis; Kemisk fysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Kemi; Chemistry; Ultrafast relaxation; Porphyrins; Delocalization; Anisotropy; Wavepacket; Vibrational Coherence; Excitons; Electronic coherence; Energy transfer; Femtosecond spectroscopy; Photosynthesis;

   Sammanfattning : Ultrafast optical response and excitation energy dynamics in light harvesting pigment-protein complexes and in a few model systems have been studied both experimentally and theoretically. Femtosecond light pulses were employed to excite the system and monitor the subsequent time evolution of the transient absorption kinetics and anisotropy. LÄS MER

5. 29. Development and analysis of turbulence models for flows with strong curvature and rotation

   Författare :Olof Grundestam; KTH; []
   Nyckelord :Turbulence model; nonlinear modelling; streamline curvature; high-lift aerodynamics;

   Sammanfattning : An explicit algebraic Reynolds stress model (EARSM) based ona pressure strain rate model including terms tensoriallynonlinear in the mean velocity gradients is developed in orderto improve predictions for .ows with strong curvature and/orrotation. LÄS MER

7. 30. The age of transported scalars in fluid mechanics

   Författare :Federico Ghirelli; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; grate furnace; velocity correlation; fluid age; scalar age; turbulence model; residence time; energy spectrum; turbulence age;

   Sammanfattning : Computational fluid dynamics (CFD) is applied to the reacting flow in the freeboard of a 30MW biofuel fired grate furnace and results are validated by comparison with data from an extensive measurement campaign. The influence of the fuel bed model on the results of the freeboard model is investigated. LÄS MER