Search for dissertations about: "Arne V. Johansson"
Showing result 1 - 5 of 10 swedish dissertations containing the words Arne V. Johansson.
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1. A study of turbulence and scalar mixing in a wall-jet using direct numerical simulation
Abstract : Direct numerical simulation is used to study the dynamics and mixing in a turbulent plane wall-jet. The investigation is undertaken in order to extend the knowledge base of the influence of the wall on turbulent dynamics and mixing. The mixing statistics produced can also be used to evaluate and develop models for mixing and combustion. READ MORE
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2. Turbulence and scalar flux modelling applied to separated flows
Abstract : The turbulen flow in an asymmetric diffuser has been en studied by the means of Reynold average Navier-Stokes equations with both differential and explict algebraic expressions to model the Reynolds stress tensor. Modifications to the differential stress model have been derived, using the inverse turbulence timescale to obtain the dissipation of turbuence kinetic energy. READ MORE
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3. Modelling of subgrid-scale stress and passive scalar flux in large eddy simulations of wall bounded turbulent flows
Abstract : The aim of the thesis is to develop and validate subgrid-scale models that are relevant for large eddy simulations of complex flows including scalar mixing. A stochastic Smagorinsky model with adjustable variance and time scale is developed by adding a stochastic component to the Smagorinsky constant. READ MORE
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4. Numerical and modelling aspects of large-eddy and hybrid simulations of turbulent flows
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
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5. Fundamental studies of non-premixed combustion in turbulent wall jets using direct numerical simulation
Abstract : The present thesis deals with the fundamental aspects of turbulent mixingand non-premixed combustion in wall-jet flows. Direct numerical simulations(DNS) of compressible turbulent flows are performed in a wall-jet configura-tion, which has a close resemblance to many industrial combustion applica-tions. READ MORE