Search for dissertations about: "turbulence modelling"

Showing result 11 - 15 of 118 swedish dissertations containing the words turbulence modelling.

2. 11. On the modelling of turbulent flow and mixing in stirred reactors

   Author : Johan Revstedt; Strömningsteknik; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; turbulence; CFD; stirred reactors; impeller modelling; Energy research; mixing; LES; Energiforskning;

   Abstract : This thesis concerns the numerical simulations and modelling of the flow structure and scalar transport in stirred reactors. For this Large Eddy Simulations (LES) have been used. The flow situation in a stirred reactor includes several flow phenomena that are not well predicted by "standard" two-equation models, e.g. READ MORE

4. 12. Application of Parallel Computers to Enhance the Flow Modelling Capability in Aircraft Design

   Author : Mattias Sillén; Dan Loyd; Peter Eliasson; Linköpings universitet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; flow modelling; parallel computer; parallel efficiency; turbulence modelling; aircraft design; CFD; Fluid mechanics; Strömningsmekanik;

   Abstract : The development process for new aircraft configurations needs to be more efficient in terms of performance, cost and time to market. The potential to influence these factors is highest in early design phases. Thus, high confidence must be established in the product earlier than today. READ MORE

5. 13. Numerical and modelling aspects of large-eddy and hybrid simulations of turbulent flows

   Author : Matteo Montecchia; Arne V. Johansson; Gert Brethouwer; Stefan Wallin; Dominic Von Terzi; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; turbulence; wall-bounded flows; large-eddy simulation; SGS modelling; OpenFOAM; hybrid RANS-LES; Engineering Mechanics; Teknisk mekanik;

   Abstract : In this study, the explicit algebraic sub-grid scale (SGS) model (EAM) has been extensively validated in wall-resolved large-eddy simulations (LES) of wall-bounded turbulent flows at different Reynolds numbers and a wide range of resolutions. Compared to eddy-viscosity based models, the formulation of the EAM is more consistent with the physics and allows to accurately capture SGS anisotropy,which is relevant especially close to walls. READ MORE

6. 14. Anisotropy-resolving subgrid-scale modelling using explicit algebraic closures for large eddy simulation

   Author : Amin Rasam; Arne Johansson; Bernard Geurts; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Turbulence; large eddy simulation; explicit algebraic subgridscale model; passive scalar; stochastic modelling; periodic hill flow; Engineering Mechanics; Teknisk mekanik;

   Abstract : The present thesis deals with the development and performance analysis ofanisotropy-resolving models for the small, unresolved scales (”sub-grid scales”,SGS) in large eddy simulation (LES). The models are characterised by a descriptionof anisotropy by use of explicit algebraic models for both the subgridscale(SGS) stress tensor (EASSM) and SGS scalar flux vector (EASSFM). READ MORE

7. 15. An Experimental Study of Reynolds Stress Closures in Shear Free and Weakly Sheared Turbulence

   Author : Dag Aronson; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; turbulence modelling; dissipation measurements; Reynolds stress closures; isotropic turbulence; anisotropic dissipation rate tensor; hot-wire anemometry; wall proximity effects; pressure strain rate correlations;

   Abstract : The objective of this thesis work is to obtain data enabling evaluation of closure hypotheses used in the Reynolds stress transport (RST) equations. Special attention has been devoted to studies of flow fields with shear free and weakly sheared turbulence. READ MORE