negative volume for the given geometry

Saha S · May 2, 2019, 17:19

I am simply trying to simulate flow over a cylinder. Having a rectangular domain and a circle at the center. I have built the case with no issue. It passed the validation. Now when I am trying to run it it is saying:
Computed a negative volume for the given geometry. Check that all of your normal vectors are pointing into the domain

How can I resolve this?

MFGT · May 3, 2019, 03:10

Hi,

Click "Normal Toggle" in the view bar to check the orientation of normal vectors.
To switch the direction, use: Geometry -> Transform -> Normal and click on one of the wrong triangles.

kbansal · May 8, 2019, 11:29

In addition to what Tobias has mentioned, please make sure that all the normals are pointing towards the fluid volume. In your case, the normals will point outside for the cylinder and inside for the rectangular domain. Thanks -Karan.

Alireza_Kakoee · July 8, 2019, 12:02

Dear friends
I am trying to model a dual fuel combustion with a geometry that contain an spherical prechamber
In my point of view there is negative volume error in pre chamber meshing, could you please let me know how can I eliminate this error?

kbansal · July 8, 2019, 13:33

Hi Alireza, what version of CONVERGE are you using? Did you check the normal orientation to see if all the normals are pointing towards the fluid domain?

Thanks,

Alireza_Kakoee · July 8, 2019, 14:09

Thank you for your reply,

My converge versión is 2.3
Direction of vectors (yellow vectors) are from each surface out.
Our fluid domain is a cylinder, close loop,
If I had your email I could send you the picture
Bests

kbansal · July 9, 2019, 10:23

Hi Alireza,

Can you post the image here if this is something shareable? If not, can you send your problem and setup to support@convergecfd.com?

Thanks,

Alireza_Kakoee · July 10, 2019, 03:11

and

MFGT · July 10, 2019, 09:12

Your triangle orientation is wrong.

Quote:

Originally Posted by MFGT

Click "Normal Toggle" in the view bar to check the orientation of normal vectors.
To switch the direction, use: Geometry -> Transform -> Normal and click on one of the wrong triangles.

Alireza_Kakoee · July 13, 2019, 04:33

thank you for your reply,

"the pre-proce4ssing error have been solved but during my run there is an error that is :
it = 600, it_out = 251, WARNING ... extrapolating on the temperature calculation
get_temp_from_sensible_sie problem found in rank 0 at cell 225809, located at < 76.0047, 0.25,"

could you please let me know what is this error related to?

Alireza_Kakoee · July 17, 2019, 05:03

I copuld make a run on converge but it consumes too many RAMs and after a fgew itertion converge automatically reduce dt to minimum and after that id is diverged

could you please let me know why? I changed grid base too many times but it doesnt work

Alireza_Kakoee · July 20, 2019, 14:01

Solved,

thank you for your cooperation

Alireza_Kakoee · July 27, 2019, 11:11

In my point of view converge 3d view have some problem in make_surface , am i right?

Alireza_Kakoee · July 27, 2019, 14:40

in non-axi-symetric geometries

May 2, 2019, 17:19	negative volume for the given geometry	#1
Saha S New Member Join Date: Jan 2016 Posts: 13 Rep Power: 10	I am simply trying to simulate flow over a cylinder. Having a rectangular domain and a circle at the center. I have built the case with no issue. It passed the validation. Now when I am trying to run it it is saying: *Computed a negative volume for the given geometry. Check that all of your normal vectors are pointing into the domain* How can I resolve this? SWalter_RSI likes this.

May 3, 2019, 03:10		#2
MFGT Senior Member Tobias Join Date: May 2016 Location: Germany Posts: 294 Rep Power: 11	Hi, Click "Normal Toggle" in the view bar to check the orientation of normal vectors. To switch the direction, use: Geometry -> Transform -> Normal and click on one of the wrong triangles. SWalter_RSI likes this.

May 8, 2019, 11:29		#3
kbansal New Member Join Date: Dec 2015 Posts: 27 Rep Power: 10	In addition to what Tobias has mentioned, please make sure that all the normals are pointing towards the fluid volume. In your case, the normals will point outside for the cylinder and inside for the rectangular domain. Thanks -Karan. __________________ Karan Bansal Senior Research Engineer CONVERGECFD

July 8, 2019, 12:02	Modeling a cylinder with spherical prechamber	#4
Alireza_Kakoee New Member Alirezak Join Date: Feb 2017 Posts: 24 Rep Power: 9	Dear friends I am trying to model a dual fuel combustion with a geometry that contain an spherical prechamber In my point of view there is negative volume error in pre chamber meshing, could you please let me know how can I eliminate this error?

July 8, 2019, 13:33		#5
kbansal New Member Join Date: Dec 2015 Posts: 27 Rep Power: 10	Hi Alireza, what version of CONVERGE are you using? Did you check the normal orientation to see if all the normals are pointing towards the fluid domain? Thanks, __________________ Karan Bansal Senior Research Engineer CONVERGECFD

July 8, 2019, 14:09	Modeling a cylinder with spherical prechamber	#6
Alireza_Kakoee New Member Alirezak Join Date: Feb 2017 Posts: 24 Rep Power: 9	Thank you for your reply, My converge versión is 2.3 Direction of vectors (yellow vectors) are from each surface out. Our fluid domain is a cylinder, close loop, If I had your email I could send you the picture Bests

July 9, 2019, 10:23		#7
kbansal New Member Join Date: Dec 2015 Posts: 27 Rep Power: 10	Hi Alireza, Can you post the image here if this is something shareable? If not, can you send your problem and setup to support@convergecfd.com? Thanks, __________________ Karan Bansal Senior Research Engineer CONVERGECFD

July 10, 2019, 03:11	negative volume	#8
Alireza_Kakoee New Member Alirezak Join Date: Feb 2017 Posts: 24 Rep Power: 9	and Last edited by Alireza_Kakoee; July 14, 2019 at 13:04.

July 13, 2019, 04:33	negative volume	#10
Alireza_Kakoee New Member Alirezak Join Date: Feb 2017 Posts: 24 Rep Power: 9	thank you for your reply, "the pre-proce4ssing error have been solved but during my run there is an error that is : it = 600, it_out = 251, WARNING ... extrapolating on the temperature calculation get_temp_from_sensible_sie problem found in rank 0 at cell 225809, located at < 76.0047, 0.25," could you please let me know what is this error related to?

July 17, 2019, 05:03		#11
Alireza_Kakoee New Member Alirezak Join Date: Feb 2017 Posts: 24 Rep Power: 9	I copuld make a run on converge but it consumes too many RAMs and after a fgew itertion converge automatically reduce dt to minimum and after that id is diverged could you please let me know why? I changed grid base too many times but it doesnt work

July 20, 2019, 14:01		#12
Alireza_Kakoee New Member Alirezak Join Date: Feb 2017 Posts: 24 Rep Power: 9	Solved, thank you for your cooperation Last edited by Alireza_Kakoee; July 22, 2019 at 11:11.

July 27, 2019, 11:11		#13
Alireza_Kakoee New Member Alirezak Join Date: Feb 2017 Posts: 24 Rep Power: 9	In my point of view converge 3d view have some problem in make_surface , am i right?

July 27, 2019, 14:40		#14
Alireza_Kakoee New Member Alirezak Join Date: Feb 2017 Posts: 24 Rep Power: 9	in non-axi-symetric geometries

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