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November 7, 2014, 05:54 |
Problem with holes in surfaces
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#1 |
Member
Robert Bischof
Join Date: Aug 2014
Posts: 56
Rep Power: 11 |
Hello there,
I have problems with surfaces in icem cfd. For the k-epsilon simulation, I didn't need to resolve the inflation layer. So the mesh was coarse for wall distance. Now I want to change to SST turbulence model and so I need to resolve the inflation layer and a low wall distance. By refining my mesh it becames bad quality. I investigated the bad region and I found a problem with my surfaces. There are Holes in my Geometry. I think, the surface can't follow the spline I imported. I import only curves from NX and built the surfaces on my own. Is there a way to avoid this problem ? |
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November 7, 2014, 08:57 |
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#2 |
Member
Robert Bischof
Join Date: Aug 2014
Posts: 56
Rep Power: 11 |
Another Example at the edge of two surfaces.
The Elements are very small, because of a low wall distance in both direction. You see, that there will be strange Elements, with bad quality. There are only a few Elements, but its only at the regions, where the wall distance is very low ? Are there problems in icem ? I think, I'am not the first, who try to get a y+-value of ~1 ?! |
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November 11, 2014, 02:33 |
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#3 |
Member
Robert Bischof
Join Date: Aug 2014
Posts: 56
Rep Power: 11 |
Can nobody help me ? I still found no solution for my problem ?
Is there a special method for meshing near wall distance to get low y+ ? Should I always use O-Grid method to mesh this regions ? |
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November 11, 2014, 10:21 |
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#4 |
Member
Join Date: Apr 2009
Location: Czech Republic
Posts: 65
Rep Power: 18 |
Extend surfaces through together. At intersection of these surfaces create curves. In Blocking for "Edge to Curve" switch ON "Project to Surface Intersection".
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November 12, 2014, 02:59 |
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#5 |
Member
Robert Bischof
Join Date: Aug 2014
Posts: 56
Rep Power: 11 |
I have tried to mesh with you tip, Ludvik, but it makes no difference.
I will give you more details of my geometry. It's a simple pipe. But I need the orange surface, it's my interface to the other part of geometry. Because of that I choose this blocking topology. I need a low wall distance in booth directions, I have drawn the red arrows. The strange things only happens, when I reach a range, in which the elements will be very small and only at first series of elements. Often at the intersection of surfaces at the edges. I try to make picture which shows my problem. For help I will be very thankful. For now I can't find solution. |
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November 12, 2014, 03:38 |
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#6 |
Member
Robert Bischof
Join Date: Aug 2014
Posts: 56
Rep Power: 11 |
I found a solution:
With this thread http://www.cfd-online.com/Forums/ans...y-small-y.html I activate the setting "Project to Bsplines" and set the "Projection limit" to 0.01. Now it works fine! |
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