scholarly journals Multilayer Numerical Modeling of Flows through Vegetation Using a Mixing-Length Turbulence Model

Water ◽  
2014 ◽  
Vol 6 (7) ◽  
pp. 2084-2103 ◽  
Author(s):  
Hector Barrios-Piña ◽  
Hermilo Ramírez-León ◽  
Clemente Rodríguez-Cuevas ◽  
Carlos Couder-Castañeda
Keyword(s):  
Numerical Modeling ◽  
Turbulence Model ◽  
Mixing Length ◽  
Numerical Modeling Of Flows

CFD Modelling of Multiphase Flows: An Overview

2003 ◽  
Author(s):  
Rajnish K. Calay ◽  
Arne E. Holdo
Keyword(s):  
Fluid Dynamics ◽  
Mass Transfer ◽  
Computational Fluid Dynamics ◽  
Numerical Modeling ◽  
Mathematical Models ◽  
Cfd Modelling ◽  
Two Phase ◽  
Wide Range ◽  
Computational Fluid Dynamics Cfd ◽  
Numerical Modeling Of Flows

The Computational Fluid Dynamics (CFD) is now increasingly being used for modeling industrial flows, i.e. flows which are multiphase and turbulent. Numerical modeling of flows where momentum, heat and mass transfer occurs at the interface presents various difficulties due to the wide range of mechanisms and flow scenarios present. This paper attempts to provide a summary of available mathematical models and techniques for two-phase flows. Some comments are also made on the models available in the commercially available codes.

scholarly journals Two-equation Turbulence Model Similarity Solution of the Axisymmetric Fluid Jet

10.14311/210 ◽  
2001 ◽  
Vol 41 (2) ◽  
Author(s):  
V. Tesař
Keyword(s):  
Turbulence Model ◽  
Similarity Transformation ◽  
Turbulence Models ◽  
Similarity Solutions ◽  
Mixing Length ◽  
Governing Equations ◽  
Satisfactory Solution ◽  
Submerged Jet ◽  
Valid Solution ◽  
Model Similarity

This paper presents a general, universally valid solution of axisymmetric turbulent submerged jet flow, for which no fully satisfactory solution has been known. What has been available so far are either computational solutions for individual particular cases, lacking universality, or similarity solutions with inadequate turbulence models, some of them based upon assumptions of a speculative character (e.g. constant mixing length across the jet profile). The present approach uses a similarity transformation of the governing equations, which incorporate an advanced turbulence model. The results are shown to be in excellent agreement with available experimental data. The new solution provides a suitable basis for analysis of enigmatic aspects of axisymmetric jets, such as their "spreading anomaly".

scholarly journals Some discussion of the nonlocal treatment of the dissipation in the Reynolds stress models

2008 ◽  
Vol 4 (S252) ◽  
pp. 45-46
Author(s):  
Tao Cai
Keyword(s):  
Reynolds Stress ◽  
Turbulence Model ◽  
Dissipation Rate ◽  
Mixing Length ◽  
Solar Convection ◽  
Stress Models

AbstractWe investigate the weakness of the present turbulence model with the nonlocal treatment of dissipation rate. A revised version is well tested for the solar convection. The suggestion of constant mixing length parameter of MLT could not hold any more if we refer to the nonlocal description of the dissipation rate, especially in the region of overshooting zone.

Prediction of Turbulent Source Flow Between Corotating Disks With an Anisotropic Two-Equation Turbulence Model

1988 ◽  
Vol 110 (2) ◽  
pp. 187-194 ◽  
Author(s):  
S. A. Shirazi ◽  
C. R. Truman
Keyword(s):  
Reynolds Number ◽  
Kinetic Energy ◽  
Turbulent Kinetic Energy ◽  
Turbulence Model ◽  
Ad Hoc ◽  
Low Reynolds Number ◽  
Wall Region ◽  
Mixing Length ◽  
Mean Flow ◽  
Low Reynolds

An anisotropic form of a low-Reynolds-number two-equation turbulence model has been implemented in a numerical solution for incompressible turbulent flow between corotating parallel disks. Transport equations for turbulent kinetic energy and dissipation rate were solved simultaneously with the governing equations for the mean-flow variables. Comparisons with earlier mixing-length predictions and with measurements are presented. Good agreement between the present predictions and the measurements of velocity components and turbulent kinetic energy was obtained. The low-Reynolds-number two-equation model was found to model adequately the near-wall region as well as the effects of rotation and streamline divergence, which required ad hoc assumptions in the mixing-length model.

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