Reynolds-Stress Modeling of 3-D Secondary Flows with Emphasis on Turbulent-Diffusion Closure

2006 ◽  
Author(s):  
Isabelle Vallet
Keyword(s):  
Reynolds Stress ◽  
Turbulent Diffusion ◽  
Secondary Flows ◽  
Stress Modeling

Reynolds-Stress Modeling of Three-Dimensional Secondary Flows With Emphasis on Turbulent Diffusion Closure

2007 ◽  
Vol 74 (6) ◽  
pp. 1142-1156 ◽  
Author(s):  
I. Vallet
Keyword(s):  
Reynolds Stress ◽  
Turbulent Diffusion ◽  
Three Dimensional ◽  
Theoretical Work ◽  
Reynolds Stress Model ◽  
Secondary Flows ◽  
Velocity Correlation ◽  
Mean Velocity ◽  
Diffusion Term ◽  
Spatial Gradients

The purpose of this paper is to assess the importance of the explicit dependence of turbulent diffusion on the gradients of mean-velocity modeling in second moment closures on three-dimensional (3D) detached and secondary flows prediction. Following recent theoretical work of Younis, Gatski, and Speziale, 2000, [Proc. Royal Society Lon. A, 456, pp. 909–920], we propose a triple-velocity correlation model, including the effects of the spatial gradients of mean velocity. A model for both the slow and rapid parts of the pressure-diffusion term was also developed and added to a wall-normal-free Reynolds-stress model. The present model is validated against 3D detached and secondary flows. Further developments, especially on the echo terms (which should appear in the formulation of pressure-velocity correlation), are discussed.

Near-Wall Turbulent Pressure Diffusion Modeling and Influence in Three-Dimensional Secondary Flows

2006 ◽  
Vol 129 (5) ◽  
pp. 634-642 ◽  
Author(s):  
E. Sauret ◽  
I. Vallet
Keyword(s):  
Diffusion Model ◽  
Turbulent Diffusion ◽  
Three Dimensional ◽  
Secondary Flows ◽  
Moment Closure ◽  
Complex Flows ◽  
Diffusion Term ◽  
Pressure Diffusion ◽  
Turbulent Pressure ◽  
Near Wall

The purpose of this paper is to develop a second-moment closure with a near-wall turbulent pressure diffusion model for three-dimensional complex flows, and to evaluate the influence of the turbulent diffusion term on the prediction of detached and secondary flows. A complete turbulent diffusion model including a near-wall turbulent pressure diffusion closure for the slow part was developed based on the tensorial form of Lumley and included in a re-calibrated wall-normal-free Reynolds-stress model developed by Gerolymos and Vallet. The proposed model was validated against several one-, two, and three-dimensional complex flows.

3D Reynolds Stress Modelling of Turbulent Flow in Linear Turbine Cascade

1997 ◽  
Author(s):  
M. Kanniche ◽  
R. Boudjemadi ◽  
F. Déjean ◽  
F. Archambeau
Keyword(s):  
Reynolds Stress ◽  
Eddy Viscosity ◽  
Strain Tensor ◽  
Secondary Flows ◽  
Turbulence Closure ◽  
Turbine Cascade ◽  
Reynolds Stresses ◽  
Mean Flow ◽  
Principal Axes ◽  
The Mean

The flow in a linear turbine cascade (Gregory-Smith et al. (1990)) is numerically investigated using a Reynolds Stress Turbulence closure. A particular attention is given to secondary flows where the normal Reynolds stresses are expected to play an important role. The most classical turbulence closure, the k-epsilon model uses the Boussinesq Eddy Viscosity concept which assumes an isotropic turbulent viscosity. The Reynolds stresses are then related to local velocity gradients by this isotropic eddy viscosity. Corollary, the principal axes of the Reynolds stress tensor are colinear with those of the mean strain tensor. The advantage of Reynolds Stress Turbulence closure is the calculation of Reynolds stresses by their own individual transport equations. This leads to a more realistic description of the turbulence and of its dependance on the mean flow. The most classical Second Order turbulence model (Launder et al. (1975)) is applied to a linear turbine cascade, and the results are compared to secondary velocity and turbulence measurements at cross-passage planes.

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