2D simulations with Reynolds Stress turbulence model

Hypothesis and Goals

The Reynolds Stress model(RSM) is the most elaborate turbulence model that FLUENT provides. Abandoning the isotropic eddy-viscosity hypothesis, the RSM closes the Reynolds-averaged Navier-Stokes equations by solving transport equations for the Reynolds stresses, together with an equation for the dissipation rate. This means that five additional transport equations are required in 2D flows.

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Simulations using RSM was compared to results from the current k-epsilon realizable (rke) model.

Methods and Procedures

Click here for a Report summary describing all modeling parameters.FlUENT settings can be found in the report summaries for k-epsilon realizable model and Reynolds stress model

Note that as opposed to k-epsilon realizable solver, RSM is quite sensitive to different specification methods of both inlet and outlet boundary conditions.

Results and Discussion

A comparison of the contours of energy dissipation contours rate, stream function and static pressure from RSM and rke is are shown below.

Energy dissipation contour of 2D model, k-epsilon realizable 1.5b
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Energy dissipation contour of 3D model with periodic boundary condition, k-epsilon realizable
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Further Research

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map from Reynolds Stress Model (2D)
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As shown above, results from the two turbulence models appear similar in terms of the lengths and shapes of the energy dissipation zone and the range of the energy dissipation value, while more detailed minor discrepancies indicates the differences of the two models in terms of their underlying assumptions and methodology.

Further Research

• RSM is quite sensitive to turbulence specification method of both inlet and out boundary conditions, thus more simulation experiments and research on the underlying methodology are needed to investigate about this parameter.
• The current comparison between RSM and RKE is quite preliminary. Comparisons of other pertinent parameters are necessary for better understanding of the models and how to choose between them for our specific flow.