Sökning: "turbulence modification"

Visar resultat 6 - 10 av 14 avhandlingar innehållade orden turbulence modification.

1. 6. 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. 7. CFD Modeling of Turbulent Flows in Industrial Applications with Emphasis on Premixed Combustion in Gas Turbines

   Författare :Ulf Engdar; Kraftverksteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; framdrivningssystem; Motorer; turbulence and premixed combustion modeling ; CFD modeling ; level-set flamelet library approach ; emissions ; gas turbine ; compressor washing ; spray modeling ; Technological sciences; Teknik; Energy research; Energiforskning; Thermal engineering; applied thermodynamics; Termisk teknik; Motors and propulsion systems; termodynamik;

   Sammanfattning : Increasing restrictions on hazardous emissions combined with demands for good profitability from the operators in the energy market have contributed strongly to the development of innovations in which the emphasis is on low emissions and high efficiency. For gas turbine-based power plants, emission of NOx in particular is governed by stringent legislation. LÄS MER

4. 8. Enhanced Radar Backscatter from the Ionosphere

   Författare :Nicola Schlatter; Nickolay Ivchenko; Noora Partamies; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : Incoherent scatter radars are powerful ground based instruments for ionospheric measurements. By analysis of the Doppler shifted backscatter spectrum, containing the signature of electrostatic plasma waves, plasma bulk properties are estimated. LÄS MER

5. 9. Boundary-layer structure in flow over a heterogeneous surface

   Författare :Patrick Samuelsson; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Earth sciences; Geovetenskap; Earth sciences; Geovetenskap; Meteorology; meteorologi;

   Sammanfattning : Airborne measurements performed within the framework of NOPEX (Northern Hemisphere Land Surface Climate Processes Experiment) have been used to study processes related to fluxes of momentum, heat, and moisture in the boundary layer in the Swedish boreal region. The NOPEX area is characterized as heterogeneous with respect to vegetation. LÄS MER

7. 10. Experimental studies in jet flows and zero pressure-gradient turbulent boundary layers

   Författare :Ramis Örlü; P. Henrik Alfredsson; Tim B. Nickels; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Axisymmetric jet; swirling jet; coaxial jet; heated jet; zero pressuregradient turbulent boundary layer; wall-bounded turbulent flows; overlap region; passive scalar mixing; hot-wire anemometry; spatial resolution.; Fluid mechanics; Strömningsmekanik;

   Sammanfattning : This thesis deals with the description and development of two classical turbulent shear flows, namely free jet and flat plate turbulent boundary layer flows. In both cases new experimental data has been obtained and in the latter case comparisons are also made with data obtained from data bases, both of experimental and numerical origin. LÄS MER