Sökning: "Buoyancy"

Visar resultat 21 - 25 av 53 avhandlingar innehållade ordet Buoyancy.

1. 21. Turbulence modeling of compressible flows with large density variation

   Författare :Igor Grigoriev; Arne Johansson; Stefan Wallin; Geert Brethouwer; Stefan Hickel; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Turbulence; DRSM; EARSM; active scalar; compressible flow; reacting flow; supercritical flow; Engineering Mechanics; Teknisk mekanik;

   Sammanfattning : In this study we highlight the influence of mean dilatation and mean density gradient on the Reynolds stress modeling of compressible, heat-releasing and supercritical turbulent flows.Firstly, the modeling of the rapid pressure-strain correlation has been extended to self-consistently account for the influence of mean dilatation. LÄS MER

3. 22. Analysis of laminar and turbulent flows with turbomachinery, biotechnology and biomechanical applications

   Författare :Gustaf Mårtensson; Arne Johansson; Gertjan van Heijst; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Fluid mechanics; Strömningsmekanik;

   Sammanfattning : The goal of this study was initially to gain a better understanding of the effects of rotation on turbulent flow in ducts. Knowledge concerning the influence of rotation on the structures of turbulence is of fundamental importance in many applications, e.g. LÄS MER

4. 23. Mechanistic Modeling of Wall-Fluid Thermal Interactions for Innovative Nuclear Systems

   Författare :Roman Thiele; Henryk Anglart; Xu Cheng; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; GEN-IV reactors; Wall heat transfer; Computational Fluid Dynamics; Wall functions; Reactor design; Supercritical water; Liquid metal; Energy Technology; Energiteknik; Fysik; Physics;

   Sammanfattning : Next generation nuclear power plants (GEN-IV) will be capable of not only producing energy in a reliable, safe and sustainable way, but they will also be capable of reducing the amount of nuclear waste, which has been accumulated over the lifetime of current-generation nuclear power plants, through transmutation. Due to the use of new and different coolants, existing computational tools need to be tested, further developed and improved in order to thermal-hydraulically design these power plants. LÄS MER

5. 24. Numerical Investigation of Rotating and Stratified Turbulence

   Författare :Enrico Deusebio; Erik Lindborg; Johan Nilsson; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Geostrophic turbulence; stable stratification; rotation; wall-bounded turbulence; gravity waves; atmospherical dynamics; direct numertical simulations; SRA - E-Science SeRC ; SRA - E-vetenskap SeRC ;

   Sammanfattning : Atmospheric and oceanic flows are strongly affected by rotation and stratification. Rotation is exerted through Coriolis forces which mainly act in horizontal planes whereas stratification largely affects the motion along the vertical direction through buoyancy forces, the latters related to the vertical variation of the fluid density. LÄS MER

7. 25. Natural Ventilation and Air Infiltration in Large Single‑Zone Buildings : Measurements and Modelling with Reference to Historical Churches

   Författare :Abolfazl Hayati; Magnus Mattsson; Mats Sandberg; Jens Fransson; Guilherme Carrilho da Graça; Högskolan i Gävle; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Natural ventilation; Airing; Air infiltration; Single-sided ventilation; Cross flow; Large single zones; Historical Churches; Model evaluation optimization; Field measurements; Wind tunnel; Indoor climate and Energy simulation; IDA-ICE; Tracer gas technique; Pressurization test.; Naturlig ventilation; Vädring; Luftinfiltration; Ensidig ventilation; Tvärdrag; Höga en-zonsbyggnader; Kulturhistoriska kyrkor; Modellutvärdering optimering; Fältmätningar; Vindtunnel; Inomhusklimat och energisimulering; IDA-ICE; Spårgas teknik; Trycksättningstest.; Hållbar stadsutveckling; Sustainable Urban Development;

   Sammanfattning : Natural ventilation is the dominating ventilation process in ancient buildings like churches, and also in most domestic buildings in Sweden and in the rest of the world. These buildings are naturally ventilated via air infiltration and airing. LÄS MER