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#21 |
Senior Member
Ruiyan Chen
Join Date: Jul 2016
Location: Hangzhou, China
Posts: 162
Rep Power: 10 ![]() |
Hi Guanjiang,
I'm using nutUSpaldingWallFunction on solid walls, which is the one I found the most robust. Again, I'm not doing very rigorous internal flow simulations, so this should not be regarded as the only choice. In fact, I know for a fact that if the mesh is fine enough, one should be able to NOT use any wall functions and get a good result. If you meant the SGS model, I'm using the standard Smagorinsky model. Although for internal flows maybe WALE is a better choice. Ruiyan |
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#22 | |
Member
Guanjiang Chen
Join Date: Apr 2020
Location: Bristol, United Kingdom
Posts: 54
Rep Power: 6 ![]() |
Quote:
Thank you for your reply! You mentioned the WALE model might be better, do you have some references? I am simulating the flow past a cylinder. The result of dynamic smagorinsky and WALE are close. The standard smagorinsky did not work well. Some papers recommend dynamic smagorinsky, while others recommend WALE. Regards, Guanjiang |
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#23 | |
Senior Member
Santiago Lopez Castano
Join Date: Nov 2012
Posts: 354
Rep Power: 16 ![]() |
Quote:
I suggest you instead to do the assessment yourself, in a case you can run without wall models, having in mind the correct grid spacings for wall-resolved LES, and post process the results. Don't stick only with the mean values of the primitive fields, also focus on getting the flow invariants. Examples: retro-calculating the Reynolds number, or Nusselt, the Strouhal number of a wake, getting the -5/3 slope for the inertial part of the energy spectrum, near-unity relation between production and dissipation near walls (at y+~11), calculating the cross correlation component of the forcings/stresses, etc. In general, in archetipal flows (and non archetipal) there are invariants that you must recover from the simulation, that depend of turbulence. I tell you this as someone who wrote an article comparing solvers and LES models, using OpenFOAM (yeah, I'm a hypocrite, I know). |
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#24 | |
Member
Guanjiang Chen
Join Date: Apr 2020
Location: Bristol, United Kingdom
Posts: 54
Rep Power: 6 ![]() |
Quote:
Thank you for your suggestions! Those are also what I am doing now. I will try my best to do that. Regards, Guanjiang |
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Tags |
les, nut, wall function |
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