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July 13, 2015, 13:55 |
Plotting of normal stresses from k-e model
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#1 |
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Join Date: Jul 2015
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i would like to ask as to how to plot the normal stresses for the k-epsilon model in fluent? I am assuming that the flow is isotropic and also that i will have to use the boussinesq relationship. However im not sure as to how to actually calculate them.
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July 15, 2015, 07:31 |
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#2 |
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B_Kia
Join Date: May 2014
Location: Ir
Posts: 123
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hi,as far i know stresses are modeled in k-e model , stresses are available in RSM
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July 15, 2015, 12:39 |
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#3 |
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Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
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I'm also trying to do the same calculation but haven't come up with a solution yet.
Note that the stresses are not isotropic, only the turbulent viscosity is isotropic. It's incorrect to say the turbulence is isotropic (since u' is not the same as v' and w'). This is very important point. I think you would have to compute the stresses from the boussinesq model from the shear and strain. But again I haven't done this part yet. Maybe in a few days or if someone else is able to post the solution. Last edited by LuckyTran; August 3, 2015 at 18:38. |
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August 14, 2015, 07:11 |
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#4 | |
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Quote:
I may have completely misunderstood everything and would be more than happy to be corrected. Last edited by Bubblyflow; August 14, 2015 at 07:13. Reason: forgot to quote |
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August 14, 2015, 18:18 |
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#5 | |
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Lucky
Join Date: Apr 2011
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Quote:
I ended up using custom field functions. The eddy viscosity hypothesis assumes that the turbulent viscosity is isotropic. It does not assume that the flow is isotropic or that the uu,vv,ww stresses equal. This is a common misconception. The assumption is that the functional relation between the strain and reynolds stresses is isotropic, whereas both the strain and reynolds stresses can be anisotropic. If you load the attached file, plz be careful as these are the proper stresses with density included. I usually compute only uu,vv,ww without the density. |
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boussinesq model, epsilon, kappa, stresses |
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