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-   -   Negative Volume (https://www.cfd-online.com/Forums/fluent/48054-negative-volume.html)

Armin April 26, 2008 16:03

Negative Volume
 
Hi there,I create a multiple zone in Gambit and later when I mesh each zone and i check my grid for any flaw Gambit does not declare any thing, but when I import the mesh into Fluent, fluent declares that my grid includes negative volume, what is the problem, tanx

AAA April 26, 2008 16:12

Re: Negative Volume
 
Hi

You probably have an "open" face that is not properly meshed or a curved edge where the mesh doesn't coincide with. I suggest you do some "Search" at the CFD-online forum for "negative volume".

Regards

AAA

armin April 27, 2008 03:18

Re: Negative Volume
 
Dear AAA I searched the site but I could not find a way to resolve the problem, I have a problem in Gambit, when I mesh a face without dividing it to some zones I do not encounter this problem but when I divide the face into some zones all the meshed cells have negative volume. tanx


AAA April 27, 2008 09:41

Re: Negative Volume
 
Hi

How do you divide the face? Do you use "Split faces" for this? Maybe you are not erasing the main face after dividing it, and this leaves you with three faces (say if one face is to be subdivided into two faces) instead of two.

Consider using the "Connect" option to get rid of any unwanted topologies.

In such cases, I'd perform one step at a time, take it to Fluent, and try to find the error.

Regards

AAA

Amir April 27, 2008 09:54

Re: Negative Volume
 
Dear Armin as AAA said You probably have an "open" face,or you have some cells that are not siutable .check your mesh whit 'examine mesh'. how do you divide your zone? can you explaine more. Best Amir

Armin April 27, 2008 16:19

Re: Negative Volume
 
first I create some edges and later I create faces out of them and I start to mesh each face separately and gambit grid check does not detect any negative volume,but when I import the grid in fluent, it declares negative volume,and later by using adapt-isovalue I find that all the cells have negative volume.


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