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

linear mesh motion in CFX

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

Like Tree1Likes

Reply
 
LinkBack Thread Tools Display Modes
Old   October 18, 2013, 16:18
Default linear mesh motion in CFX
  #1
Senior Member
 
ali
Join Date: Oct 2009
Posts: 157
Rep Power: 7
alinik is on a distinguished road
Hi Guys,

I want to know how I can define a linear mesh motion in CFX?
In Basic setting>Domain models>Domain motion I can only define rotating kind of motion, not simple translational motion.

Thanks
alinik is offline   Reply With Quote

Old   October 20, 2013, 20:07
Default
  #2
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,797
Rep Power: 84
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
You need to use moving mesh and define the translation.
ghorrocks is offline   Reply With Quote

Old   October 20, 2013, 20:14
Default
  #3
Senior Member
 
ali
Join Date: Oct 2009
Posts: 157
Rep Power: 7
alinik is on a distinguished road
I can only define rotary motion. I can not find translational motion in the domain motion menu. could you please more specific how I can define translational motion?

Thanks
alinik is offline   Reply With Quote

Old   October 20, 2013, 20:17
Default
  #4
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,797
Rep Power: 84
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
You are looking in moving frames of reference. The only available option is rotating. I am talking about moving mesh - this is a different thing.
ghorrocks is offline   Reply With Quote

Old   October 20, 2013, 20:22
Default
  #5
Senior Member
 
ali
Join Date: Oct 2009
Posts: 157
Rep Power: 7
alinik is on a distinguished road
thank, but I am looking in this menu and I cannot find it
Basic setting>Domain models>Domain motion

can you please tell me where I have to look to define mesh motion?
and by the way what is the difference between mesh motion and domain motion?
If the translational option is provided in CFX it will be a life saver for me.

Thanks
alinik is offline   Reply With Quote

Old   October 20, 2013, 20:41
Default
  #6
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,797
Rep Power: 84
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
Because it is not under domain motion. It is under mesh deformation (it used to be called moving mesh, sorry about that).
ghorrocks is offline   Reply With Quote

Old   October 25, 2013, 15:07
Default
  #7
Senior Member
 
ali
Join Date: Oct 2009
Posts: 157
Rep Power: 7
alinik is on a distinguished road
Glenn,

There is only one option under mesh deformation and it is called "Regions of motion specified". When I choose it, I get to choose mesh motion model and the only option available is "displacement diffusion" in which I can set the mesh stiffness model, etc.

I can not see any option by which I can introduce linear mesh motion in CFX.
could you please more specific.

I am using CFX 12.0.1

Thanks
alinik is offline   Reply With Quote

Old   October 26, 2013, 06:49
Default
  #8
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,797
Rep Power: 84
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
The option might not be available in V12. The current version is V14.5, and the beta of V15 is already out. Time to update to the current version I think.
ghorrocks is offline   Reply With Quote

Old   October 28, 2013, 09:48
Default
  #9
Senior Member
 
Bruno
Join Date: Mar 2009
Location: Brazil
Posts: 236
Rep Power: 12
brunoc is on a distinguished road
Quote:
Originally Posted by alinik View Post
There is only one option under mesh deformation and it is called "Regions of motion specified". When I choose it, I get to choose mesh motion model and the only option available is "displacement diffusion" in which I can set the mesh stiffness model, etc.

I can not see any option by which I can introduce linear mesh motion in CFX.
could you please more specific.

I am using CFX 12.0.1

Thanks
You're looking at the domain settings, so you just activated mesh motion. To actually create mesh motion, go to the boundary condition you want to move and you'll see a new tab there to define the motion itself.

In case you want to move the entire domain, create a subdomain that includes the entire domain you want to move, and set the motion in there.

You'll need to inform a CEL Expression that describes the motion in both cases.

BTW, do update to a newer version. The mesh smoother is a bit better, plus remeshing is a little easier (but just a little).
brunoc is offline   Reply With Quote

Old   March 24, 2014, 19:06
Default
  #10
Senior Member
 
ali
Join Date: Oct 2009
Posts: 157
Rep Power: 7
alinik is on a distinguished road
Quote:
Originally Posted by brunoc View Post
You're looking at the domain settings, so you just activated mesh motion. To actually create mesh motion, go to the boundary condition you want to move and you'll see a new tab there to define the motion itself.

In case you want to move the entire domain, create a subdomain that includes the entire domain you want to move, and set the motion in there.

You'll need to inform a CEL Expression that describes the motion in both cases.

BTW, do update to a newer version. The mesh smoother is a bit better, plus remeshing is a little easier (but just a little).

Thank you very much Brunoc and Glenn

Now I have upgraded to R15 and have enabled beta features. Still I cannnot see the options you guys are saying. I have activated mesh motions but in neither of the boundaries I can see any tabs being added.
Brunoc do you have a similar simulation? If yes can you post the ccl here so that I can take a look at it? I am following you especially where you say I need to inform a CEL expression that...
I want to model wakes originating from a series of Rods that are moving upwards in a domain. I have tried many other options and it seems that enabling this linear sliding mesh is going to be the only solution.
So I guess I have to introduce CELs for inlet? am I right?
Is there a tutorial that explains this fully in details. I really need to do this.

Any help is much appreciated
alinik is offline   Reply With Quote

Old   March 25, 2014, 05:27
Default
  #11
New Member
 
Peter
Join Date: Sep 2011
Location: Germany
Posts: 23
Rep Power: 5
PeMo is on a distinguished road
Have a look at this tutorial
http://www.edr.no/index.php/blogg/an...cfx_re_meshing
It explains the basic function of moving mesh and automatic remeshing.
Also you see the additional tabs and CEL Bruno was referring to.
2015mohammad2015 likes this.
PeMo is offline   Reply With Quote

Old   April 1, 2014, 12:44
Default
  #12
Senior Member
 
ali
Join Date: Oct 2009
Posts: 157
Rep Power: 7
alinik is on a distinguished road
PEMO,

Thanks for this tutorial. This is exactly what I am looking for. the problem is the simulation ends before it starts. and I receive this message:



--> Final synchronization point reached by all partitions.

+--------------------------------------------------------------------+
| An error has occurred in cfx5solve: |
| |
| The ANSYS CFX solver exited with return code 1. |
+--------------------------------------------------------------------+

End of solution stage.

+--------------------------------------------------------------------+
| The following transient and backup files written by the ANSYS CFX |
| solver have been saved in the directory |
| /scratch/nikp11/WD/remeshing/remeshing_001: |
| |
| 0.trn |
+--------------------------------------------------------------------+


+--------------------------------------------------------------------+
| The results from this run of the ANSYS CFX Solver have been |
| written to /scratch/nikp11/WD/remeshing/remeshing_001.res |
+--------------------------------------------------------------------+


My domain consists of two domains, one of them is stationary and the other one is the one that is supposed to have moving rods in it. I do every thing step by step according to this example but I do not know why it ends before it starts. It is not even giving me a good description of error.

any help is much appreciated.

Thanks
alinik is offline   Reply With Quote

Old   April 1, 2014, 21:00
Default
  #13
Senior Member
 
ali
Join Date: Oct 2009
Posts: 157
Rep Power: 7
alinik is on a distinguished road
any idea PEMO?
alinik is offline   Reply With Quote

Old   April 2, 2014, 05:59
Default
  #14
New Member
 
Peter
Join Date: Sep 2011
Location: Germany
Posts: 23
Rep Power: 5
PeMo is on a distinguished road
Difficult to say what caused the error depending on this snippet. Have a look at the trn and res file for any wrong initialization and boundary setting. Also I would switch off any solver equation (expert parameter), set the coefficent loop to 1 and an appropriated time step. So you can have a look only at the moving mesh, to be sure there is no folding and negative cell volumes during the expected simulation time.
PeMo is offline   Reply With Quote

Old   April 7, 2014, 14:50
Default
  #15
Senior Member
 
ali
Join Date: Oct 2009
Posts: 157
Rep Power: 7
alinik is on a distinguished road
PEMO

I fixed the previous problem but now I have this new error:


+================================================= ===================+
| ****** PROBLEM REPORT ****** |
|--------------------------------------------------------------------|
| Subsystem: Input and Output |
| Subroutine name: ErrAction |
| Severity level: Fatal Error |
| Error message number: 001100279 |
|--------------------------------------------------------------------|
| Message: |
| |
| REDHDR: locating dataset failed: what=G/NAMEMAP where=EVERY |
| |
| |
| |
| |
| |
+================================================= ===================+
WARNING: CFXSTP, Regression check error.

+--------------------------------------------------------------------+
| An error has occurred in cfx5solve: |
| |
| Error interpolating results onto the new mesh: |
| /g/software/ansys_inc/v150/CFX/bin/linux-amd64/double/solver-pcmp- |
| i.exe exited with return code 1. |
+--------------------------------------------------------------------+

It seems that it is due to lack of enough memory. I have increased the memory allocation factor but still have this issue.
Have you ever had such error before?

Thanks,

Ali
alinik is offline   Reply With Quote

Old   April 10, 2014, 18:35
Default
  #16
Senior Member
 
ali
Join Date: Oct 2009
Posts: 157
Rep Power: 7
alinik is on a distinguished road
Guys,

apparently it is not a memory issue. I checked the error log file and it says that one of the boundaries(the one that is moving) is not valid and hence it is not recognized. I do not know what to do?
alinik is offline   Reply With Quote

Old   April 10, 2014, 18:37
Default
  #17
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,797
Rep Power: 84
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
Yes, it is unlikely the error is a memory issue. Messages like this tell you very little about what the error actually is. All you can do is simplify your model until it runs, then add the complex bits back in one at a time until you get the error again. Then you know where the error comes from.
ghorrocks is offline   Reply With Quote

Old   April 10, 2014, 18:48
Default
  #18
Senior Member
 
ali
Join Date: Oct 2009
Posts: 157
Rep Power: 7
alinik is on a distinguished road
I can not simplify it any more. it is now a very small domain in which two rods are moving upwards and all surrounding boundaries are no-slip wall.
It says that :
the location of boundary "ROD1" is invalid
Region "ROD1" is not recognised.
the location of boundary "ROD2" is invalid
Region "ROD1" is not recognised.

Any ideas?
alinik is offline   Reply With Quote

Old   April 10, 2014, 19:34
Default
  #19
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,797
Rep Power: 84
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
Looks like you have found it - your boundaries ROD1 and ROD2 are not correctly defined. Delete them and redefine them.
ghorrocks is offline   Reply With Quote

Old   April 10, 2014, 20:00
Default
  #20
Senior Member
 
ali
Join Date: Oct 2009
Posts: 157
Rep Power: 7
alinik is on a distinguished road
Did that and ran it again.
Still the same error.
any other ideas?
alinik is offline   Reply With Quote

Reply

Thread Tools
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 On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Moving mesh Niklas Wikstrom (Wikstrom) OpenFOAM Running, Solving & CFD 122 June 15, 2014 06:20
Dynamic mesh motion using CFX Anant CFX 5 February 27, 2014 08:17
Dynamic moving mesh Pei-Ying Hsieh (Hsieh) OpenFOAM Running, Solving & CFD 64 June 7, 2012 10:04
Prescribed mesh motion does not correspond to actual motion rbarrett CFX 8 June 30, 2011 13:22
CFX mesh & ICEM mike CFX 3 April 27, 2006 15:27


All times are GMT -4. The time now is 12:23.