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OpenFoam, SALOME, all free tools for engineers
Old

PISO's strange behavior at different meshes :(

Posted February 25, 2013 at 07:19 by skeptik (CFD notes)

1. mesh quad+tri+3D extruded. at 17 grad most flow around airfoil is laminar

Name:  piso_17_hybrid.jpg
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2. mesh only tri+3D extruded. at 15 grad flow behind foil is completely turbulent

Name:  piso15_wake.jpg
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so this pictures shows that we cannot get proper results for Cx, Cy due to bad prediction of the flow detachment.

try to find a solution, may be OF 2.1 will show better results
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Old

Good news about airfoil and OpenFoam

Posted February 20, 2013 at 03:42 by skeptik (CFD notes)

So, at the end of the testing OpenFOAM/simpleFoam, i get:

NACA23012
U=21.3, Re=0.44e6,

LowRe case, LaunderSharmaKE:
1. OF 1.7 cannot solve the case with kEpsilon on hex+tetra 2D mesh. It just crashes.

2. There are a lots of details when you use LowRe LSkEps model, you need lots of iteration, lots of interpolation data to provide better accuracy.

3. People invented k-omega for different flows near the walls. And better one - kOmega...
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Old

Hey, Dude, be careful with liftDir/dragDir in controlDict

Posted February 19, 2013 at 05:41 by skeptik (CFD notes)

When U is changed due to angle of attack you should change controlDict in libForces section.

So, what can you get when you have proper controlDict

U=56.4, Re=1.6e6

Name:  kOmega_Epsilon.jpg
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The mesh was refined so it was OK after checkMesh

Name:  hybrid_refined.jpg
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not bad) the next - recalculate LowRe K-eps, just for fun.
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