CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > CONVERGE

Warning while doing simulation

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   April 16, 2021, 03:49
Default Warning while doing simulation
  #1
New Member
 
tianyuan Xia
Join Date: Apr 2021
Posts: 10
Rep Power: 5
hudehfu is on a distinguished road
Hello everyone:
When I started running the simulation,the following warning appears before reading the file.

1850 WARNING: There may be an alignment error.
The maximum dot product of the motion vector with a non-moving or reloft triangle's normal vector is 5.418371e-04.
For properly aligned moving surfaces, this dot_product should be less than 5.0e-4

1851 WARNING: The boundary type that appears to not be aligned is WALL, and it is attached to boundary 1, which is moving.
The triangle of maximum alignment error is centered at -1.149003e-02 -3.960107e-02 -2.961063e-02

Will these warnings affect the simulation? What is the cause of these warnings?
hudehfu is offline   Reply With Quote

Old   April 19, 2021, 17:21
Default
  #2
Senior Member
 
ksrivast's Avatar
 
Kislaya Srivastava
Join Date: Sep 2017
Location: Convergent Science, Northville MI
Posts: 165
Rep Power: 8
ksrivast is on a distinguished road
Hello Tianyuan,

When non-moving boundary triangles are attached to moving boundaries, CONVERGE will check for alignment errors. For example, for an IC engine simulation, you want your liner triangles to be aligned to your piston motion direction and thus be perfectly cylindrical. If not aligned (ex. a tapered liner), your simulations might face mass conservation issues as the non-moving triangles stretch/compress when the moving triangles they are attached to move.

You are strongly recommended to rectify these alignment issues in your geometry before running your case.

Sincerely,
__________________
Kislaya Srivastava
Principal Research Engineer | Applications
CONVERGECFD
ksrivast is offline   Reply With Quote

Old   April 19, 2021, 23:14
Default
  #3
New Member
 
tianyuan Xia
Join Date: Apr 2021
Posts: 10
Rep Power: 5
hudehfu is on a distinguished road
Quote:
Originally Posted by ksrivast View Post
Hello Tianyuan,

When non-moving boundary triangles are attached to moving boundaries, CONVERGE will check for alignment errors. For example, for an IC engine simulation, you want your liner triangles to be aligned to your piston motion direction and thus be perfectly cylindrical. If not aligned (ex. a tapered liner), your simulations might face mass conservation issues as the non-moving triangles stretch/compress when the moving triangles they are attached to move.

You are strongly recommended to rectify these alignment issues in your geometry before running your case.

Sincerely,
Dear ksrivast:
thank you for your reply. I have a few more questions as follows:

What effect does this error have on the simulation?
How do I locate the geometric location in the model where the error occurs?
Can I find the place where the error occurred in CONVERGE?
Can I fix this error in CONVERGE?

Looking forward to your reply. I also want others to help me, thanks.
hudehfu is offline   Reply With Quote

Old   April 20, 2021, 09:16
Default
  #4
Senior Member
 
ksrivast's Avatar
 
Kislaya Srivastava
Join Date: Sep 2017
Location: Convergent Science, Northville MI
Posts: 165
Rep Power: 8
ksrivast is on a distinguished road
Hello Tianyuan,

1. Your simulations can face mass conservation issues if you have this error.
2. CONVERGE has reported the boundary ID the misaligned triangles were attached to. For your case, it is boundary ID 1. Please check alignment of all triangles attached to boundary ID 1.
3. CONVERGE has also reported the x,y,z location of the affected triangle in the log file. Thus, you can easily find the geometric location in CONVERGE Studio.
4. You would need to properly align your triangles in your surface file to fix this issue.

Sincerely,
__________________
Kislaya Srivastava
Principal Research Engineer | Applications
CONVERGECFD
ksrivast is offline   Reply With Quote

Old   April 20, 2021, 09:47
Default
  #5
New Member
 
tianyuan Xia
Join Date: Apr 2021
Posts: 10
Rep Power: 5
hudehfu is on a distinguished road
Quote:
Originally Posted by ksrivast View Post
Hello Tianyuan,

1. Your simulations can face mass conservation issues if you have this error.
2. CONVERGE has reported the boundary ID the misaligned triangles were attached to. For your case, it is boundary ID 1. Please check alignment of all triangles attached to boundary ID 1.
3. CONVERGE has also reported the x,y,z location of the affected triangle in the log file. Thus, you can easily find the geometric location in CONVERGE Studio.
4. You would need to properly align your triangles in your surface file to fix this issue.

Sincerely,
Thanks again for your reply。
What is the operation flow of alignment? Or where can I get the learning materials for alignment operations?
I hope you can give me some guidance,thanks.
hudehfu is offline   Reply With Quote

Old   April 20, 2021, 09:54
Default
  #6
Senior Member
 
ksrivast's Avatar
 
Kislaya Srivastava
Join Date: Sep 2017
Location: Convergent Science, Northville MI
Posts: 165
Rep Power: 8
ksrivast is on a distinguished road
Hello Tianyuan,

Please attend our CONVERGE for IC Engines introduction training sessions, or have a look at the training slides available in our downloads webpage, where we go into detail on how to check for and properly align triangles attached to moving boundaries. Ex, that of Liner and valve top.

Sincerely,
__________________
Kislaya Srivastava
Principal Research Engineer | Applications
CONVERGECFD
ksrivast is offline   Reply With Quote

Old   April 20, 2021, 10:09
Default
  #7
New Member
 
tianyuan Xia
Join Date: Apr 2021
Posts: 10
Rep Power: 5
hudehfu is on a distinguished road
Quote:
Originally Posted by ksrivast View Post
Hello Tianyuan,

Please attend our CONVERGE for IC Engines introduction training sessions, or have a look at the training slides available in our downloads webpage, where we go into detail on how to check for and properly align triangles attached to moving boundaries. Ex, that of Liner and valve top.

Sincerely,
Thank you very much for your reply.
But I didn't find the training slides you mentioned. Can you send me a training slide by email or a link to the download ?

Thank you very much again
hudehfu is offline   Reply With Quote

Old   April 20, 2021, 10:16
Default
  #8
Senior Member
 
ksrivast's Avatar
 
Kislaya Srivastava
Join Date: Sep 2017
Location: Convergent Science, Northville MI
Posts: 165
Rep Power: 8
ksrivast is on a distinguished road
Hello Tianyuan,

If you haven't already, please register to create an account on our website. Once approved, you can login to your account and access the training material.

Sincerely,
__________________
Kislaya Srivastava
Principal Research Engineer | Applications
CONVERGECFD
ksrivast is offline   Reply With Quote

Old   April 20, 2021, 21:29
Default
  #9
New Member
 
tianyuan Xia
Join Date: Apr 2021
Posts: 10
Rep Power: 5
hudehfu is on a distinguished road
Quote:
Originally Posted by ksrivast View Post
Hello Tianyuan,

If you haven't already, please register to create an account on our website. Once approved, you can login to your account and access the training material.

Sincerely,
Thank you for your reply. I have registered my account。 But I couldn't find training material。May I ask which module I can find the training materials in?
hudehfu is offline   Reply With Quote

Old   April 22, 2021, 17:16
Default Training material
  #10
yli
Member
 
Yanheng Li
Join Date: Jan 2016
Location: Convergent Science, Madison WI
Posts: 33
Rep Power: 10
yli is on a distinguished road
You can register for any of your upcoming training session (online) from our calendar and our coordinator will share the training material/cases with you.



For converge documation (manual, etc.), you can find in

YOUR_CONVERGE-PACKAGE/Convergent_Science/CONVERGE/3.0.20/doc
__________________
Yanheng Li
Research Engineer-Applications

CONVERGECFD
yli is offline   Reply With Quote

Reply

Tags
alignment error, warning

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
[blockMesh] Errors during blockMesh meshing Madeleine P. Vincent OpenFOAM Meshing & Mesh Conversion 51 May 30, 2016 10:51
[snappyHexMesh] How to define to right point for locationInMesh Mirage12 OpenFOAM Meshing & Mesh Conversion 7 March 13, 2016 14:07
Cells with t below lower limit Purushothama Siemens 2 May 31, 2010 21:58
OpenFOAM Solaris mamaly60 OpenFOAM Installation 13 May 10, 2010 21:16
Compilation errors in ThirdPartymallochoard feng_w OpenFOAM Installation 1 January 25, 2009 06:59


All times are GMT -4. The time now is 22:44.