A Note in Comment on “A Reynolds Stress Model for Turbulent Corner Flows”

1977 ◽  
Vol 99 (3) ◽  
pp. 593-595 ◽  
Author(s):  
Ronald M. C. So
Keyword(s):  
Reynolds Stress ◽  
Shear Flows ◽  
Reynolds Stress Model ◽  
Turbulent Shear ◽  
Stress Model ◽  
General Applicability ◽  
Closure Models ◽  
Closure Scheme ◽  
Stress Components ◽  
Corner Flows

In [1] Gessner and Emery proposed a closure scheme for the Reynolds-stress equations such that the resultant equations are algebraic and can be solved for the various stress components for corner flows. This note summarizes the earlier work on such closure models for different kinds of turbulent shear flows which was omitted by Gessner and Emery and comments on the general applicability of the model proposed by Gessner and Emery.

A Reynolds Stress Model for Turbulent Corner Flows—Part II: Comparisons Between Theory and Experiment

1976 ◽  
Vol 98 (2) ◽  
pp. 269-276 ◽  
Author(s):  
F. B. Gessner ◽  
J. K. Po
Keyword(s):  
Reynolds Stress ◽  
Reynolds Stress Model ◽  
Length Variation ◽  
Stress Model ◽  
Duct Flow ◽  
Rectangular Duct ◽  
Proposed Model ◽  
Alternate Model ◽  
Corner Flows ◽  
Good Agreement

The applicability of the Reynolds stress model developed in Part I to fully developed rectangular duct flow is investigated. Two sets of experimental data are analyzed in order to prescribe a representative mixing length variation and appropriate values for the constants in the model. Predicted Reynolds stress values are in good agreement with their experimental counterparts for both sets of data. These results are compared with predictions referred to an alternate model in order to explain discrepancies observed in a previous study. Possible extensions of the proposed model to increase its flexibility are discussed.

A Reynolds Stress Model for Turbulent Corner Flows—Part I: Development of the Model

1976 ◽  
Vol 98 (2) ◽  
pp. 261-268 ◽  
Author(s):  
F. B. Gessner ◽  
A. F. Emery
Keyword(s):  
Reynolds Stress ◽  
Flow Behavior ◽  
Reynolds Stress Model ◽  
Turbulence Structure ◽  
Stress Model ◽  
Mixing Length ◽  
Corner Flow ◽  
Global Representation ◽  
Corner Flows ◽  
Algebraic Reynolds Stress Model

A Reynolds stress model is proposed for modeling the local turbulence structure in flow along a streamwise corner. Initial discussion centers on present methods of predicting internal and extenal corner flow behavior. An algebraic Reynolds stress model is then developed by operating on a modified form of the Reynolds stress transport equations. Application of the model involves specification of two empirical constants and a global representation for the mixing length. The paper concludes with a discussion of the features and limitations of the model.

Prediction of Heat Transfer in a Ribbed Channel: Evaluation of Unsteady RANS Methodology

2005 ◽  
Author(s):  
William D. York ◽  
D. Scott Holloway ◽  
James H. Leylek
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Reynolds Stress ◽  
Flow Direction ◽  
Reynolds Stress Model ◽  
Navier Stokes ◽  
Stress Model ◽  
Clemson University ◽  
Ribbed Channel ◽  
Closure Models

Heat transfer in a straight channel with rib turbulators on one wall is predicted numerically with an unsteady Reynolds-averaged Navier-Stokes (URANS) methodology and compared to code-validation quality experimental data from the literature. Additionally, for comparison, steady simulations of the problem are conducted using two popular turbulence closure models, a Realizable k-ε model and a differential Reynolds-stress model. Closure in the URANS simulation is provided by a new eddy-viscosity-based model that was developed in the Advanced Computational Research Laboratory at Clemson University. This new model consists of three transport equations, and it is designed specifically to promote natural unsteadiness in the flow without the need for artificial forcing. In all cases, the Reynolds number, based on hydraulic diameter, is equal to 24,000. Eight square ribs, orthogonal to the flow direction, are equally spaced on the bottom wall of the channel. For the URANS simulation, after the flow becomes fully-developed in the streamwise direction, the predicted Nusselt number on the ribbed wall follows the trend of measured data from the modeled experimental study. However, the unsteady simulation slightly overpredicts the distance to the peak heat transfer aft of each rib. Also, the heat transfer prediction is very dependent on the grid resolution aft of the ribs. Therefore, efficient refinement of the unstructured mesh and grid-independence issues are discussed. Results of both steady simulations show a significant underprediction of Nusselt number over the entire ribbed wall, with the Reynolds-stress model giving the better result of the two steady closure models. The results of this study clearly show that unsteady vortex shedding off of the ribs is important in the physics of this problem, and a systematic, unsteady methodology is necessary to accurately predict ribbed-channel heat transfer.

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