TGrid High Skewness

khimkhim · January 30, 2010, 13:30

Hi all,

I'm using TGrid 5.0.6 to mesh my model AHU room's interior with the boundary meshes imported from Gambit.

In TGrid, after i mesh the interior with Tri/Tet., i keep having high skewness, as high as 0.99904423 (max.)
I've tried to reduce it by "Auto Node Move" function which manage to reduce the skewness to < 0.9 on the same model before. The only different between this model with the previous one is that the inlet location has translated 0.55m, on the same face.

I'm following exactly the same procedure as i did for the first model but this time, the skewness just couldn't go down.
How else can i reduce the skewness?

I've check the boundary mesh before i start meshing the volume. And the max. skewness of the boundary mesh would be 0.89.

Another thing is that before i check the mesh quality, i've check "Mesh Limits" under "Report", and the no. of cells are 5M++ whereas for my first model (which is basically the same in every aspect as mentioned above), the no. of cells is only 1M++. Why for such 2 identical models, the no. of cells will have such great difference. I'm actually having memory limitation here when goes into FLUENT.

Where has i gone wrong?

udayrg · February 18, 2010, 00:36

hi

Well i feel you need to check the surface mesh count, This would certainly change the total mesh count.

And for skewness correction if more than two node of the tet lie on surface or in other words if for a cell (tetrahedral) which has four nodes if more than two node are on the surface mesh it is impossible for Tgrid to remove the skewness. Look out for this possibility in your mesh.

Uday

January 30, 2010, 13:30	TGrid High Skewness	#1
khimkhim New Member Ch'ng Huey Khim Join Date: Nov 2009 Posts: 11 Rep Power: 17	Hi all, I'm using TGrid 5.0.6 to mesh my model AHU room's interior with the boundary meshes imported from Gambit. In TGrid, after i mesh the interior with Tri/Tet., i keep having high skewness, as high as 0.99904423 (max.) I've tried to reduce it by "Auto Node Move" function which manage to reduce the skewness to < 0.9 on the same model before. The only different between this model with the previous one is that the inlet location has translated 0.55m, on the same face. I'm following exactly the same procedure as i did for the first model but this time, the skewness just couldn't go down. How else can i reduce the skewness? I've check the boundary mesh before i start meshing the volume. And the max. skewness of the boundary mesh would be 0.89. Another thing is that before i check the mesh quality, i've check "Mesh Limits" under "Report", and the no. of cells are 5M++ whereas for my first model (which is basically the same in every aspect as mentioned above), the no. of cells is only 1M++. Why for such 2 identical models, the no. of cells will have such great difference. I'm actually having memory limitation here when goes into FLUENT. Where has i gone wrong?

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February 18, 2010, 00:36		#2
udayrg Member Join Date: Mar 2009 Posts: 32 Rep Power: 17	hi Well i feel you need to check the surface mesh count, This would certainly change the total mesh count. And for skewness correction if more than two node of the tet lie on surface or in other words if for a cell (tetrahedral) which has four nodes if more than two node are on the surface mesh it is impossible for Tgrid to remove the skewness. Look out for this possibility in your mesh. Uday