non-positive volume
 

in fluent while reading the mesh i am getting the error "non-positive volumes exist" grid check failed.. why is this error occurring ??

Re: non-positive volume
 

try to check your mesh in gambit first... maybe, some face is not meshed or same volume does not exist.

Ihope it's helpful. Adriano

Re: non-positive volume
 

ya.. from a cylinder ..using substract option i have removed an inner cylinder from the initial cylinder..and i have meshed the remaining annular region using interval count..cooper mesh.. and when i read it using fluent.. it said the above error.. can u say where i did the error

Re: non-positive volume
 

I have had the same problem two days before. I`m not an expert, but I read in another message of this forum that this error may be caused by a very little size of the intervals in your mesh. The program can`t deal with the mesh so it handles the mesh generated as it was composed by negative volumes.

In conclusion, use a mesh less fine (biger size of the intervals). I did it and it works.

Re: non-positive volume
 

Hi guys,

Negative is generated when the equi-angle skew of your voule mesh is 1.

As cristina suggested reduce the size of your face meshes as this would reduce the skewness of your face meshes from where the volume mesh is generated.

In general keep the skewness of your surface meshes to less than 0.7.

Hope these are helpful.

Ta

Regards

Rohan

Re: non-positive volume
 

Hello, to get rid of the negative volumes , i suggest to use ADAPT region or volume , u an put the Min and MAx , then it will for sure be done . in this way , u will use the ADAPT for only the volume that shows the error or need more intervals .

Re: non-positive volume
 

If you are using Gridgen, negative volumes are read when the co-ordinate system is specified as left handed. Fluent can only handle right handed co-ordinate systems. Re-specify i,j (eta, zeta) for the gird and try re-importing into fluent.