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LRR Rstm pipe flow takes too long to get fully developed

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Old   February 13, 2010, 11:26
Default LRR Rstm pipe flow takes too long to get fully developed
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Dear foamers,

I'm setting up a pipe flow and comparing this to Eggels data for pipe flow at Re = 5500. k-omega-SST yields "almost" satisfying results, and now I'm trying with LRR Rstm turbulence model instead. So far the plots for 'k' seems ok, but a thing that worries me is that it takes so long for the flow to get fully developed.

I include here a screenshot with a number of different plots, showing how axial velocity varies along the entire pipe length, and far beyond the "5 X diameter" rule.

Also included is the residuals plot. I feel it's clearly something fishy going on here, as the pressure and U_y and U_z never drops below 0.001, even though they they are set in fvSolutions (both tolerance and relTol) to limits far below.

Suggestions on to how to improve this?
Attached Images
File Type: jpg LRR1_2.jpg (91.1 KB, 37 views)
File Type: png residual1.png (26.1 KB, 24 views)
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