Sökning: "Turbulent flow"

Visar resultat 11 - 15 av 465 avhandlingar innehållade orden Turbulent flow.

1. 11. 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. 12. Direct numerical simulation of turbulent flow in plane and cylindrical geometries

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

   Sammanfattning : 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. LÄS MER

4. 13. Large Eddy Simulation of Turbulent Compressible Jets

   Författare :Bernhard Semlitsch; Mihai Mihaescu; Laszlo Fuchs; Paul G. Tucker; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Compressible Flow; Large Eddy Simulation; Acoustic Noise Generation; Near-field Acoustics; Flow Control; Optimization; Modal Flow Decomposition; Engineering Mechanics; Teknisk mekanik;

   Sammanfattning : Acoustic noise pollution is an environmental aggressor in everyday life. Aero- dynamically generated noise annoys and was linked with health issues. It may be caused by high-speed turbulent free flows (e.g. LÄS MER

5. 14. Supersonic flow separation with application to rocket engine nozzles

   Författare :Jan Östlund; KTH; []
   Nyckelord :turbulent; boundary layer; shock wave; interaction; overexpanded; rocket nozzle; flow separation; control; side-load; experiments; models; review;

   Sammanfattning : The increasing demand for higher performance in rocketlaunchers promotes the development of nozzles with higherperformance, which basically is achieved by increasing theexpansion ratio. However, this may lead to flow separation andensuing instationary, asymmetric forces, so-called side-loads,which may present life-limiting constraints on both the nozzleitself and other engine components. LÄS MER

7. 15. Turbulence measurements in fiber suspension flows : experimental methods and results

   Författare :Monika Carina Fällman; Fritz Bark; Daniel Söderberg; Fredrik Lundell; Thomas Wikström; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; fluid; flow; turbulent; turbulence; paper; pulp; fiber; fibre; suspension; two-phase; experimental; conductivity; micro-probes; passive scalar; ultrasonic; Doppler shift; Fluid mechanics; Strömningsmekanik;

   Sammanfattning : Turbulent mixing is present in many pulp and paper processes. It is a particularly important factor in the design and improvements of the paper machine headbox, influencing the final paper structure. LÄS MER