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Everything you need to compute DNS in channel vs OF 2.1.0

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Old   July 9, 2013, 07:00
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Lev
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initial conditions were U=0,p=0. And then flow developed to the "quasi steady state" of turbulence flow.
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Old   March 3, 2014, 21:08
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Huang Xianbei
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Hi
I just follow your idea of adding a source term representing the grad(p) in the UEqn, I made my domain as 12.56*2*6.28m in 3 orientation. The fluid is water whose nu =1e-6m2/s, the grad(p)=3.8e-8m/s2, however, the solution turns to be strange that the residual of Uy,Uz and p increase after a certain timesteps, the residual of p approches about 0.5. Also, the velocity along the y direction increases steadily along timestep, so the solution can converge, what may be the problem? My grid is 64*128*64
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Old   March 6, 2014, 22:27
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Huang Xianbei
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Hi,lev:
Another question(probably very simple). In the controlDict in your test case, the application name is solver_DNS, while the solver you defined is ico_DNS, is this should be "ico_DNS' insteady?
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Old   March 25, 2014, 21:21
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Hi:
I use the perturbU to make a initial field, setting the maximum streak to be at y+=12 by modifying the perturbU.C. However, the solution takes long time to reach a perhaps fully developed flow after 40000s, also ,the result is not good, as you can see

the velocity is higher than the loglaw when y+>30, I don't know how to generate a more proper initial field, can anyone help?
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Old   July 9, 2014, 15:11
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Kent Wardle
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Any chance someone can repost the files for ico_dns solver? I am unable to get them from sendspace.

~ EDIT ~

Never mind. I got it now. Thanks for sharing.

Last edited by kwardle; July 10, 2014 at 10:59.
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Old   July 6, 2015, 16:46
Default Same set up calculation using icoFoam
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Roro Wang
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Hi Lev,

Your work looks very amazing. Thanks for the contribution. I tried to use icoFoam directly to reproduce your work but found the mean velocity profile is ok, but the u_rms is much off. So I guess it's due to your modification to the original icoFoam. I noticed you modified the pressure term. Could you explain why and is there any reference to your modification?

Update: Got the reason, i.e. the modification applied a constant pressure gradient. Everything works great now.

Thanks a lot.
foamWang

Last edited by foamWang; July 6, 2015 at 23:49.
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