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-   -   Meshing in CHT Problem (http://www.cfd-online.com/Forums/fluent/111505-meshing-cht-problem.html)

 Markat January 8, 2013 16:24

Meshing in CHT Problem

I try to mesh my geometry (thin plate). The minimum orthogonal quality is about 0.1 and the average about 0.9. The residuals are about 1e-05 after 1000 iterations and can not be further reduced.
Some elements have negative value of wall heat transfer, which I cannot physically explain.
1. Is it important to use inflation or should I ignore inflation to achieve a better minum orthogonal quality?
2.Should I try to use Polyherdal meshing to improve minimum orthogonal quality? Can Polyherdal meshing be used for CHT problems? When I used Polyhedral meshing the maximum value of wall heat transfer was being almost doubled in comparison with Tetrameshing. How could you explain this?

 Markat January 10, 2013 16:56

 Markat January 13, 2013 13:36

Does anybody have any idea?

 diamondx January 13, 2013 13:59

post screenshot of you mesh !! and your geometry !! is it 2d or 3d ?? what software did you use to mesh ??

 Markat January 13, 2013 14:45

 diamondx January 13, 2013 14:57

can i see how it looks like

 Markat January 13, 2013 16:14

I unfortunately don't have an availiable picture of my meshing right now, but I will post one as soon as possible! Thank you in advance for your help

 Markat January 13, 2013 16:16

Just to imagine it looks like an thin airfoil in a wind tunnel. Only a the fluid was being meshed (I used boolean subtraction to create the appropriate geometry).

 diamondx January 13, 2013 16:38

it should be easy to mesh with a structured mesh under ICEM are you familiar with icem. when the geometry is easy; always go for a structured mesh if you can.

 Markat January 13, 2013 16:45

Thank you for your advice! I tried to do a structured mesh! Unfotunately the mesh in the area near the airfoil (cambered) can not be structured.
When I try smoothing the meshing in Fluent I got a better minimum orthogonal quality (~0.4). The simulation result remained unchanged (energy residuals do not ger below 10^-5 so I thought I should try to solve my problem transient)!

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