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-   -   Negative volumes using Gridgen in Fluent 6.1 (http://www.cfd-online.com/Forums/fluent/38500-negative-volumes-using-gridgen-fluent-6-1-a.html)

Tom November 5, 2005 17:52

Negative volumes using Gridgen in Fluent 6.1
 
Hi,

I've created a very simple 2D circular cylinder grid using gridgen, to test out the program. When I import the grid into Fluent and check the grid, negetive volumes show up and all of the faces are left-handed.

I've tried running the elliptical solver to improve the grid but to no avail.

Any help with this is much appreciated.

Thanks.

John Chawner November 6, 2005 15:05

Re: Negative volumes using Gridgen in Fluent 6.1
 
Hi Tom,

2D grids for Fluent must be in the x-y plane. Might that be the problem when you exported Fluent's native files?

When you examine the grid in Gridgen, what does it report for cell volume (area)? All positive or negative?

If you're not using the native Fluent export and instead are using the "raw" grid export (e.g. PLOT3D), you'll have to make sure the surface grid's orientation is correct in Gridgen. You can do this by making a 2D block and setting the direction.

Hope this helps.

dpshaka November 8, 2005 07:20

Re: Negative volumes using Gridgen in Fluent 6.1
 
you can perform a 3d computation ,but it has only one cell in the third dirction. you have a negative volume ,perhapas because the reason of pole point . regards


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