Too much trim on the ship and "zero or negative volume" error

alderemert · February 3, 2022, 12:09

I've been trying to simulate a drift test of an inland vessel in shallow waters by morphing mesh but I just got this error message in the middle of the simulation: "Tank have zero or negative volume".

When I check the scenes, it looks terribly trimmed but I don't know how to fix the problem. I am new to STAR-CCM+ as well. Does someone have an idea?

Scenes: https://imgur.com/a/6GAgy0M

Isaac_Newton · February 6, 2022, 13:17

Hey alderemert,

It seems a problem during your CAD to Body conversion. Do you have used the Repair Surface command to check your surface? Or even checked at the Repair CAD?

If you ran the Repair Surface did you have reached some pierced or free edges?

If you can, run the Repair Surface and post the image to help us understand what is happening way better.

Bye!

alderemert · February 7, 2022, 21:48

Quote:

Originally Posted by Isaac_Newton

Hey alderemert,

It seems a problem during your CAD to Body conversion. Do you have used the Repair Surface command to check your surface? Or even checked at the Repair CAD?

If you ran the Repair Surface did you have reached some pierced or free edges?

If you can, run the Repair Surface and post the image to help us understand what is happening way better.

Bye!

Hello!

Thanks for the recommendation, I came across 93 pierced faces that appear to be at propellers.

https://imgur.com/i7XWcPF

If that's the whole reason for that trim, what can be done to eliminate these pierced surfaces?

Isaac_Newton · February 7, 2022, 22:24

Yes, probably the reason for this issue are the pierced faces. You have two main ways to deal with these faces:

1 - Try the Star CCM auto repair surface command (save you simulation before this), with a low number of pierced faces as you have, normally this command works well. But save first, because sometimes this command changes your whole geometry and you can't undo.

2 - Other solution is delete the pierced faces, but do this each one at a time, because you will need to use the repair commands to recreate your surface manually. Probably when you delete, you will reach some free edge issues, but as you manually recreate the path you solve these free edges problems.

I hope this information can help you, if not feel free to ask again and we could try a different way.

If it works please write here, it could help more people.

Good job!

February 3, 2022, 12:09	Too much trim on the ship and "zero or negative volume" error	#1
alderemert New Member Join Date: Feb 2022 Posts: 6 Rep Power: 4	I've been trying to simulate a drift test of an inland vessel in shallow waters by morphing mesh but I just got this error message in the middle of the simulation: "Tank have zero or negative volume". When I check the scenes, it looks terribly trimmed but I don't know how to fix the problem. I am new to STAR-CCM+ as well. Does someone have an idea? Scenes: https://imgur.com/a/6GAgy0M

February 6, 2022, 13:17		#2
Isaac_Newton New Member Join Date: Sep 2021 Posts: 6 Rep Power: 5	Hey alderemert, It seems a problem during your CAD to Body conversion. Do you have used the Repair Surface command to check your surface? Or even checked at the Repair CAD? If you ran the Repair Surface did you have reached some pierced or free edges? If you can, run the Repair Surface and post the image to help us understand what is happening way better. Bye!

February 7, 2022, 22:24		#4
Isaac_Newton New Member Join Date: Sep 2021 Posts: 6 Rep Power: 5	Yes, probably the reason for this issue are the pierced faces. You have two main ways to deal with these faces: 1 - Try the Star CCM auto repair surface command (save you simulation before this), with a low number of pierced faces as you have, normally this command works well. But save first, because sometimes this command changes your whole geometry and you can't undo. 2 - Other solution is delete the pierced faces, but do this each one at a time, because you will need to use the repair commands to recreate your surface manually. Probably when you delete, you will reach some free edge issues, but as you manually recreate the path you solve these free edges problems. I hope this information can help you, if not feel free to ask again and we could try a different way. If it works please write here, it could help more people. Good job!