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

mesh motion help request

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

Reply
 
LinkBack Thread Tools Display Modes
Old   July 25, 2013, 04:30
Default mesh motion help request
  #1
New Member
 
James
Join Date: Jun 2013
Posts: 16
Rep Power: 4
JAlbert is on a distinguished road
Hello everybody;

I am going to model pitching naca 0012 in CFX. I am a new user. I have two questions.

1- In order to simulate pitsh motion which means have mesh motion, Is it true to rotate all the domain with specified angular velocity or do I have to make one region near airfoil and one outer and just rotate the inner region ( one in near airfoil)? Does it make any difference in results ? If there is no difference, I think rotating the entire domain would be easier, of course velocity direction of inlet is still fixed in ,for example ,X-direction.

2-In Fluent there is an option which you can see contours of any variable or mesh motion every time step in calculation activities, solution animation part. Is there such a capability in CFX?How to do that?

Thanks in advance.
JAlbert is offline   Reply With Quote

Old   July 25, 2013, 08:05
Default
  #2
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,937
Rep Power: 85
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
This would be best done by putting the airfoil in a rotating frame of reference and linking it with the rest of the stationary geometry by a GGI. THen you can isolate the rotating bit to just around the airfoil and your outer boundaries do not need to move.
ghorrocks is offline   Reply With Quote

Old   July 26, 2013, 02:27
Default
  #3
New Member
 
James
Join Date: Jun 2013
Posts: 16
Rep Power: 4
JAlbert is on a distinguished road
Thank you Glenn for your reply;

As you know, in order to use reference frame I must activate "Rotating" in that region near airfoil. Now I want to know :

1- Should I activate mesh deformation option for any of rotating or stationary subdomains or not? I have meshed the inner region with boundary layer quality and I do not want my initial mesh quality change during solution.

2- What about plunge simulation? Should I divide the domain into two subdomains again or , no, oscilating the entire domain vertically will yield in physical results?

Thanks a lot for your kind.
JAlbert is offline   Reply With Quote

Old   July 27, 2013, 07:02
Default
  #4
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,937
Rep Power: 85
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
Only use rotating frames of reference if he only motion is rotary. If other motions are present I would not use it but then use a general moving mesh.

What is a plunge simulation?
ghorrocks is offline   Reply With Quote

Old   July 27, 2013, 09:20
Default
  #5
New Member
 
James
Join Date: Jun 2013
Posts: 16
Rep Power: 4
JAlbert is on a distinguished road
By plunge simulation, I mean translating the airfoil vertically by a Sine function ,for example. Now do I have to separate the domain into two subdomains or no one entire domain is enough? How does CFX start to remesh? In fluent you can choose whether just smooth the domain or both smooth and remesh. How does remeshing option activates in CFX?

Thanks a lot.
JAlbert is offline   Reply With Quote

Old   July 28, 2013, 07:33
Default
  #6
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,937
Rep Power: 85
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
If the foil is translating (not rotating) then you need to use moving mesh, at least for that application. I would do it as one moving mesh domain. But make sure the outer boundaries do not move (unless they are meant to move).

Yes, CFX supports remeshing.
ghorrocks is offline   Reply With Quote

Old   July 29, 2013, 08:31
Default
  #7
New Member
 
James
Join Date: Jun 2013
Posts: 16
Rep Power: 4
JAlbert is on a distinguished road
Thanks for your reply;

Is it possible to monitor mesh displacement or mesh motion in CFX during CFX solution like Fluent mesh animation option?
JAlbert is offline   Reply With Quote

Old   July 29, 2013, 21:40
Default
  #8
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,937
Rep Power: 85
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
Yes. Define a monitor point with a CEL expression to look at Mesh X/Y/Z Displacement.
ghorrocks 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
how to set periodic boundary conditions Ganesh FLUENT 13 January 22, 2014 05:11
Mesh motion with Translation & Rotation Doginal CFX 2 January 12, 2014 07:21
Star CCM Overset Mesh Error (Rotating Turbine) thezack CD-adapco 3 December 11, 2013 04:09
3D Hybrid Mesh Errors DarrenC ANSYS Meshing & Geometry 11 August 5, 2013 06:42
3D valve motion but no mesh motion with smoothing slaol2 FLUENT 1 September 22, 2011 18:06


All times are GMT -4. The time now is 16:30.