Sökning: "near-wall models"

Visar resultat 1 - 5 av 27 avhandlingar innehållade orden near-wall models.

1. 1. Turbulence Modelling of Flows Related to Wall-Cooling Applications

   Författare :Stefan Jansson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; low-Reynolds number models; second-order-moment closures; turbulent heat transfer; two-equation models; film-cooling; near-wall models; turbulence modelling;

   Sammanfattning : Engineering flows are generally characterised by complex strain field and turbulence structure arising from a combination of shear, curvature, separation and recirculation etc. Under such flow conditions, transport by turbulent velocity fluctuations can make a significant contribution to the transport of momentum, heat and mass. LÄS MER

3. 2. Numerical Simulation of High Reynolds Number Wall Bounded Flow

   Författare :Tobias Persson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; subgrid model; DES; high; validation; LES; numerical simulation; near-wall;

   Sammanfattning : In this thesis, four different numerical methods are used for predictions of high Reynoldsnumber (Re), wall bounded flows; Large Eddy Simulation (LES) with two different subgrid(turbulence) models, the One Equation Eddy Viscosity model (OEEVM) and the MixedModel (MM), Monotone Integrated LES (MILES), Detached Eddy Simulation (DES) andReynolds Averaged Navier Stokes (RANS). The LES calculations are combined with a wallmodel based on the law-of-the-wall and in DES a hybrid RANS/LES method is used forhandling the near wall region. LÄS MER

4. 3. Analysis of the Performance of Different V2F Turbulence Models in a Stator Vane Passage Flow

   Författare :Andreas Sveningsson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; heat transfer; RANS; realizability; V2F; stator flow;

   Sammanfattning : When designing the cooling system of modern gas turbines it is important to be able to predict the heat transfer from the hot gas to the walls surrounding the gas path. One flow feature making this rather complicated is the presence of secondary, three-dimensional flow structures, often referred to as horse shoe vortices, which greatly enhance the rate of heat transfer to the endwall, especially in the leading edge region. LÄS MER

5. 4. 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

7. 5. Large Eddy Simulation of the Flow around a High-Lift Airfoil

   Författare :Simon Dahlström; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; mildly separation; hybrid RANS LES; incompressible finite volume; airfoil; transition; large Eddy simulation; approximate wall boundary condition;

   Sammanfattning : The work presented in this thesis concerns the efforts of conducting a Large Eddy Simulation (LES) around an airfoil. The airfoil is close to stall, near maximum lift and the Reynolds number is high. In the flow a transitional separation bubble is present. LÄS MER