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nutUSpaldingWallFunсtion gets wrong pressure component of force

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Old   June 17, 2014, 07:49
Default nutUSpaldingWallFunсtion gets wrong pressure component of force
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Alexander
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Hello to all.
I have some problems with evaluation of forces in LES calculation (Smagorinsky model) using nutUSpaldingWallFunction. I use pimpleDyMFoam as a solver in staticFvMesh mode.

Firstly I would like to describe my problem: I calculate flows over ellipsoid (diameter/length 1:6) and when I have small attack angles (from 0 to 10) I get forces very similar to forces calculated with RANS mathod of the same case. But above 20 degrees - I get forces very different to boundary conditions and type of simulation.

If I use nutUSpaldingWallFunction, the range of forces is about:
forces(pressure,viscous)
(37.50837233 -0.3207277896 92.56263734),(19.32228817 7.494549963e-06 -0.6408733014)
moment(pressure,viscous)
(-0.06406177929 67.70941945 -0.1111197376),(3.2437242e-05 0.3007978313 0.0001052868578)

But if I set zeroGradient I get forces:
forces(pressure,viscous)
(133.3884806 2.771016793 270.0308506),(58.4344816 0.05374480749 -5.308788023)
moment(pressure,viscous)
(0.3386124596 51.09489828 0.5863830054),(0.002957706558 2.333681177 0.005048023672)

And finally if I simulate my problem in laminar mode I get forces:
forces(pressure,viscous)
(86.36685283 -2.51870395 186.002309),(4.126058039 0.0002311758685 -0.9988433552)
moment(pressure,viscous)
(-0.46235493 53.11159684 -0.8013332792),(0.0001077252326 0.0819613383 -1.885974301e-05)
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