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-   -   Methodology for turbulence model sensitivity (http://www.cfd-online.com/Forums/fluent/80806-methodology-turbulence-model-sensitivity.html)

Sarah October 7, 2010 04:38

Methodology for turbulence model sensitivity
 
Hi all,

In my research (buoyant air flow in rooms with cold inlet air) I see that the influence of turbulence models is rather large (more important than the mesh sensitivity). I used standard k-e, RNG k-e, realizable k-e and SST k-w.
I do not have validation data available, so have to try to explain the differences by analyzing the theoretical background of the models. I am reading literature and studying the theory, but would still like some help on how to start with analyzing my results.
I would start like this:
  • Plot of streamlines
    • Logical flow pattern?
    • Compare flow defining features, like recirculation length, attachment length, separation point location, stagnation point location,.. to quantify differences
  • Plots of turbulent quantities: compare and try to explain differences based on the theoretical model (tips and tricks on this?)
    • Turbulent kinetic energy k
    • Turbulent dissipation rate e
    • Turbulent dissipation frequency w
    • Turbulent viscosity μt
    • Wall shear stress tw
    • Production of k
    • Effective viscosity
    • Blending functions for SST k-w (available in Fluent output?)

I realize this is very difficult, but I think here the experience from long-time users is very valuable.
Thanks for your input!

Sarah


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