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Norasikin Mat Isa October 5, 2007 09:18

Grid check failed
Hello everyone! I created a 2D mesh in GAMBIT but when I import it in fluent 6 I have a warning during check Grid: "WARNING: non-positive face area exist!" What's the problem? Please, can someone help me. Thank you.

PratiK Mehta October 5, 2007 09:24

Re: Grid check failed
first check if u have saved the *msh file by ticking export 2d .Also so whether u have opened 2d fluent n not 3d

Norasikin Mat Isa October 5, 2007 09:27

Re: Grid check failed
I've checked that. But I still get the same warning. Thanks.

PratiK Mehta October 5, 2007 09:29

Re: Grid check failed
I guess then u should check it out in gambit to remesh the system. What mesh are u using

Norasikin Mat Isa October 5, 2007 09:34

Re: Grid check failed
I used tri. I made a triangle shape at inlet as I want fine meshing there and I mesh the rest.

PratiK Mehta October 5, 2007 09:46

Re: Grid check failed
Cells with a negative volume can often be identified using the Iso-Value Adaption capability to mark them for adaption and view them in the graphics window.

Have u mentioned the dimensions of the domain correctly.

Negative volumes means that u have disconnectivity within your domain, so make sure u have done a connectivity check in gambit.

Norasikin Mat Isa October 5, 2007 10:06

Re: Grid check failed
Thanks. I will try that. One more question. Which one should I do first?... grid - check.. or define - solver ( axisymmetric)?.. because.. if i do grid - check first.. i won't get that message... if i do define- solver.. then grid check... i will get that message. Can you explain why?. I do just half of tank and have an axis. Thank.

Sun October 6, 2007 23:32

Re: Grid check failed
make sure that the min volume isn't negative during Grid checking

WTTO October 7, 2007 22:55

Re: Grid check failed
Before import mesh to FLUENT, check your grid in GAMBIT and make sure that the negative volume not exist by examine mesh tool. If still there, you can redistribute mesh untill you get free of negative volume (area).

Rameche Candane October 11, 2007 03:44

Re: Grid check failed
What you are supposed to do is the following:

When you create the geometry try creating it in mm (millimeters) rather than in m. Its obvious that you cant specify the unit in GAMBIT but create the geometry in mm (ex if the length is 1meter make it 1000 mm if not create it in cms) Then try reading the mesh in FLUENT after specifying the scale there as mm you wont have any problem.

Regards, Rameche Candane. S

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