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-   -   [ICEM] discontinuous region over vorticity (http://www.cfd-online.com/Forums/ansys-meshing/130028-discontinuous-region-over-vorticity.html)

jyh3134 February 18, 2014 12:49

discontinuous region over vorticity
 
3 Attachment(s)
Hi, all

I've studyed 3d Wing recently
but I can't deal with some region where quantities show discontinuity especially Vorticity magnitude.

The reason I think is fine grid spacing near LE, wing tip without reasonable stretching ratio or asepct ratio caused by blocking topology.

But I want mesh refinement in there, and can't change blocking strategy.
(due to sharp TE and wingtip, I employed H-grid type.

here are details of simulation.
grid generation : Icem CFD multiblock hexa
(determinant quality above 0.4, angle > 0.3, no negative volume)
solver : fluent
Re=1.2e6
k-omega SST
node based, 2nd order, steady, AoA=8deg

Thanks in advance.
best&regards

gotang February 20, 2014 08:30

Your problem is very clearly a mesh dependency issue, as the non-physical gradients that you observe align on your block boundaries. You say that you cannot change your block structure - why not? It is important to avoid the skewness that you have produced close to the LE of the aerofoil, due to the flow stagnation close by. If your aerofoil has a sharp TE, then you should use a C-grid around the aerofoil itself, which can then join on to an H-grid in the outer region.


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