Turbulent Wall Flows
Mostrando 1-12 de 14 artigos, teses e dissertações.
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1. Feasible domain of Walker's unsteady wall-layer model for the velocity profile in turbulent flows
O presente trabalho estuda em detalhe o modelo parietal transiente de Walker et al. (1989, AIAA J., 27, 140-149) para perfis de velocidade em escoamentos turbulentos. Dois novos termos são adicionados ao sistema transcedental não linear de equações que é utilizado para determinar os três principais parâmetros do modelo. Os domínios matemático e fís
An. Acad. Bras. Ciênc.. Publicado em: 2014-12
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2. On the evaluation of linear and non-linear models using DNS data of turbulent channel flows
In this paper, a priori and a posteriori analyses of algebraic linear and non-linear models are carried out in order to compare their ability to predict near wall turbulent flows. Tests were done using data from a direct numerical simulation (DNS) of a plane channel flow for three Reynolds numbers, based on the friction velocity, Reτ = 180, Reτ = 395 and R
J. Braz. Soc. Mech. Sci. & Eng.. Publicado em: 2012-12
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3. The numerical modeling of thermal turbulent wall flows with the classical κ - ε model
The goal of this work is to propose a new methodology to simulate turbulent thermal wall flows using the classical κ - ε model. The focus of this approach is based on the manner used to implement heat flux boundary conditions on the solid walls. In order to explain and to validate this new algorithm, several test cases are presented, testing a great range
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2011-03
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4. Um estudo numérico sobre a transferência de calor na camada limite turbulenta
The present work is a numerical study on the applicaion of analogies between heat and momentum difusion as a methodology to impose heat flux boundary conditions in turbulent boundary layer flows. In order to validate the proposed methodology the following cases were tested: a) a study of turbulent flows over slightly heated flat plates and with unheated star
Publicado em: 2009
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5. Implementação dos efeitos da não linearidade do tensor de Reynolds em modelos de turbulência baseados na hipótese de Boussinesq / Implementation of non linear effects of Reynolds tensor on turbulence models based on Boussinesq approximation
The main goal of this work is to implement and evaluate the correction proposed by Spalart [53] on turbulence models based on Boussinesq approximation. The objective of this correction is to capture non linear effects of Reynolds tensor, which are not correctly predicted and modeled by Boussinesq approximation. In his work, Spalart [53] proposed the correcti
Publicado em: 2009
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6. NUMERICAL STUDY OF THE INTERACTION BETWEEN A SUPERSONIC JET AND PLANAR SURFACE / ESTUDO NUMÉRICO DA INTERAÇÃO ENTRE UM JATO SUPERSÔNICO E UMA SUPERFÍCIE PLANA
I in this work a study of the interaction between a supersonic jet and a planar surface is presented, with the aim to analyze the behavior of the velocity, pressure and temperature flowfield. This study finds its motivation in the process of thermal spallation of hard rocks, which may result from the interaction between a high pressure and high temperature j
Publicado em: 2008
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7. Advanced turbulence modelling for complex aerospace applications.
The objective of the present research work consists in studying complex aerodynamic flows about typical aerospace configuration, in which turbulence effects play a fundamental role. Such study is performed with an available computational tool that is being developed at CTA/IAE. This is a finite-volume code for unstructured 3-D meshes that solves the compress
Publicado em: 2007
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8. A K − W turbulence model for near-wall thermal flows / Um modelo k − w para escoamentos turbulentos parietais dilatáveis
The main goal of this work is to extend the K − W turbulence model proposed by Bredberg (2002), originally developed in order to simulate turbulent isothermal flows in which adverse pressure gradients occur, to simulate the effects of density variations exclusively due to the presence of thermal gradients - cases vastly applied in industry - implementi
Publicado em: 2006
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9. The pulsed wire anemometer: review and further developments
The purpose of the present paper is to review work that has been done on the pulsed wire anemometer technique and also suggest further developments that could be made in its range of application. The aper discusses the three types of probes that have been used in pulsed wire anemometry: the crossed wire velocity probe, the parallel wire wall shear stress pro
Journal of the Brazilian Society of Mechanical Sciences. Publicado em: 2000
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10. A law of the wall formulation for recirculating flows
This work presents a new law of the wall formulation for recirculating turbulent flows. An alternative expression for the internal length which can be applied in the separated region is also presented. The formulation is implemented in a numerical code which solves the k-epsilon model through a finite volume method. The theoretical results are compared with
Journal of the Brazilian Society of Mechanical Sciences. Publicado em: 2000
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11. An experimental/numerical study of the turbulent boundary layer development along a surface with a sudden change in roughness
A theory for the description of turbulent boundary layer flows over surfaces with a sudden change in roughness is considered. The theory resorts to the concept of displacement in origin to specify a wall function boundary condition for a kappa-epsilon model. An approximate algebraic expression for the displacement in origin is obtained from the experimental
Journal of the Brazilian Society of Mechanical Sciences. Publicado em: 2000
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12. Transfer of a passive additive in a turbulent boundary layer at very large Reynolds numbers
We formulate the mass transfer problem for a passive additive in a turbulent boundary layer based on the recently proposed model of the turbulent boundary layer at very large Reynolds numbers. The solutions of three basic problems are obtained. These solutions are self-similar asymptotics describing the mass exchange at its initial stages. The solutions obta
The National Academy of Sciences.