Sökning: "k-.omega."

Visar resultat 1 - 5 av 8 avhandlingar innehållade ordet k-.omega..

1. 1. Numerical Simulation of Turbulent Flows for Turbine Blade Heat Transfer Applications

   Författare :Jonas Larsson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; k-.omega.; k-.epsilon.; explicit Runge-Kutta; finite volume; turbine; numerical method; non-linear; Navier-Stokes; supersonic; two-equation; external heat transfer; stagnation flow; two-dimensional; transition; low-Reynolds; turbulence model; impulse blade;

   Sammanfattning : Turbine blade heat transfer is an important engineering problem characterized by complex flow fields and high turbulence levels. This thesis is focused on using a full Navier-Stokes solver with two-equation eddy-viscosity models to predict external heat-transfer in single-stage, linear, two-dimensional uncooled turbine cascades. LÄS MER

3. 2. The Full Multigrid Method Applied to Turbulent Flow in Ventilated Enclosures Using Structured and Unstructured Grids

   Författare :Peter Emvin; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; adaptivity; finite volume; local mesh refinement; finite element; k-omega large Eddy simulation; ventilated enclosure; k-epsilon; multigrid;

   Sammanfattning : Computational fluid dynamics require large computer resources and it is thus of paramount interest to have as efficient an algorithm as possible. This means that both an accurate discretization and a fast solver are required. In this work, we have used the full multigrid concept, which is a general and optimal solver. LÄS MER

4. 3. 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

5. 4. Assessment and Some Improvements of Hybrid RANS-LES Methods

   Författare :Sebastian Arvidson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; LES; hybrid RANS-LES; zonal RANS-LES; embedded LES; PDH-LRN; log-layer mismatch; LES length scale; shock boundary-layer interaction;

   Sammanfattning : Motivated by numerical analysis of a shock/boundary-layer interacting (SBLI) flow in a duct, where some typical existing hybrid RANS-LES methods become awkward to give accurate predictions of the shock-induced corner separation bubble, a new hybrid RANS-LES method, has been proposed. The model is based on a low-Reynolds-number (LRN) $k-\omega$ RANS model, which is one of the few models that are capable of giving reasonable predictions for the SBLI flow in RANS computations. LÄS MER

7. 5. Dynamics of Vortices and Charges in Two Dimensional Arrays of Small Josephson Junctions

   Författare :ChiiDong Chen; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : This thesis is based on experimental work on two dimensional (2D) Josephson junction arrays. The junctions are small (~ 0.004~0.04 µm2) so that the charging energy E~ e2/2C associated with the junction capacitance C is large. LÄS MER