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Report of turbulentDFSEMInlet BC Applied on Wall-Model LES Simulation |
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April 24, 2020, 07:17 |
Report of turbulentDFSEMInlet BC Applied on Wall-Model LES Simulation
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#1 |
Member
Sereff
Join Date: Jan 2019
Posts: 48
Rep Power: 7 |
Hi Foamers
I was running a case with the following seup, where turbulentDFSEMInlet (developed base on an article by Poletto, R., Craft, T., & Revell, A. (2013)https://www.researchgate.net/publica...itions_for_LES) is applied at the inlet and I noticed some issues: Code:
> Atmospheric Boundary Layer; > resolution (64 64 64); > dimension (6282 1000 3141); // [m] > turbulentModel > kEqn(LES); > Boundary Conditions: > ground > noSlip; > upAtmosphere > inletOutlet; > Inlet > turbulentDFSEMInlet; > Outlet > zeroGradient; > front > cyclic; > back > cyclic; > turbulentDFSEMInlet Entries: > Ubulk (21.3 0 0); // [m/s] > U obtained from cyclic LES simulation; > L obtained from cyclic LES simulation; > R obtained from cyclic LES simulation; > delta 1000; // half-channel height [m] Code:
// Inialise eddy box extents forAll(*this, faceI) { scalar& s = sigmax_[faceI]; s = mag(L_[faceI]); // s = 6.62 s = min(s, kappa_*delta_); // s = 410 s = max(s, nCellPerEddy_*cellDx[faceI]); // s = 490 // s = min(s, nCellPerEddy_*cellDx[faceI]); // s = 6.62 } I then tried another path to "fix" it. In eddy.C file I found the following code where the eddy intensity was calculated (Foam::eddy::setScales, line 42), Code:
for (label beta = 0; beta < 3; ++beta) { scalar x = slos2 - 2*lambda[beta]/sigma2[beta]; if (x < 0) { alpha[beta] = 0; ok = false; } else { alpha[beta] = e[beta]*sqrt(x/(2*c2)); // alpha[beta] = e[beta]*sqrt(7.5e-4*x/(2*c2)); } } Kind regards, |
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April 24, 2020, 07:25 |
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#2 |
Member
Sereff
Join Date: Jan 2019
Posts: 48
Rep Power: 7 |
Some more plots on the modified case results, it can be seen that the flow is not fully-developed yet (x/delta = 6). But it is comparable with the results from channel395DFSEM tutorial case https://www.openfoam.com/documentati...nnel-flow.html.
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