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

3D sliding meshes

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

Reply
 
LinkBack Thread Tools Display Modes
Old   September 4, 2014, 18:55
Exclamation 3D sliding meshes
  #1
lml
New Member
 
Minliang Liu
Join Date: Jul 2014
Posts: 5
Rep Power: 3
lml is on a distinguished road
Hi everyone, I am struggling with a 3D sliding meshes simulation of mixer utilizing a rotating rod. I set unit in micrometer in workbench DM.
I have done simulation in 2D successfully. It's a single rod rotating in a channel. 2 velocity inlets inject 2 different liquid which have same property as liquid water, pressure outlet...use species transport model
I set a static zone and the other is a moving zone. (the rod is in the moving zone) the moving zone is a cylinder, which means the static zone has 3 faces interact with the moving zone. these 6 faces (plus the faces in the static zone) are set to be interface. (I made the setup similar as 2D simulation)
starting fluent, I set the 6 faces as 3 pairs in mesh interfaces setting.
however, when running the simulation everything goes well expect that the fluid couldn't enter the moving zone. in the result contours, I checked the velocity and mass fraction, it showed that the data in static and moving zone were not connected well, the moving zone did rotate but the interfaces acted as "walls" to block the liquid to flow into the moving zone.
lml is offline   Reply With Quote

Old   September 5, 2014, 07:40
Default
  #2
Senior Member
 
Cees Haringa
Join Date: May 2013
Location: Delft
Posts: 265
Rep Power: 6
CeesH is on a distinguished road
Hi,

Just to be sure, you did match the interfaces under `mesh interfaces' right? (otherwise the simulation probably wouldn't run anyway...)
Your problem sounds curious, I don't see a particular reason why it wouldn't work. Did you try MRF as well? Does that work?
CeesH is offline   Reply With Quote

Old   September 5, 2014, 10:51
Default
  #3
lml
New Member
 
Minliang Liu
Join Date: Jul 2014
Posts: 5
Rep Power: 3
lml is on a distinguished road
Quote:
Originally Posted by CeesH View Post
Hi,

Just to be sure, you did match the interfaces under `mesh interfaces' right? (otherwise the simulation probably wouldn't run anyway...)
Your problem sounds curious, I don't see a particular reason why it wouldn't work. Did you try MRF as well? Does that work?
I didn't try MRF
I created the name selection in Mesh cell
Is it correct to match the 6 interfaces as 3 pairs? the solution was converged but solved 2 zone separately.
I noticed in the boundary condition window there were several "walls" and I couldn't see them in display meshes option. ( I identified the walls belong to static zone)
lml is offline   Reply With Quote

Old   September 5, 2014, 11:55
Default
  #4
Senior Member
 
Cees Haringa
Join Date: May 2013
Location: Delft
Posts: 265
Rep Power: 6
CeesH is on a distinguished road
There are quite often some `empty' walls in the b.c.'s, shouldn't be a problem.

With 3 pairs of interfaces, do you mean a pair `top', `bottom' and `side' or something else? If you mean something else, it may be a problem, because every interface should be pared with every interface it can slide along I think. But in the top, bottom, middle case that should work.

A simple but easy to overlook thing may be a wrong definition of the rotation axis?

And I think you should try MRF - it shouldn't take much time, and if that does work, you may rule out some potential issues already.
CeesH is offline   Reply With Quote

Old   September 5, 2014, 22:07
Default
  #5
lml
New Member
 
Minliang Liu
Join Date: Jul 2014
Posts: 5
Rep Power: 3
lml is on a distinguished road
Quote:
Originally Posted by CeesH View Post
There are quite often some `empty' walls in the b.c.'s, shouldn't be a problem.

With 3 pairs of interfaces, do you mean a pair `top', `bottom' and `side' or something else? If you mean something else, it may be a problem, because every interface should be pared with every interface it can slide along I think. But in the top, bottom, middle case that should work.

A simple but easy to overlook thing may be a wrong definition of the rotation axis?

And I think you should try MRF - it shouldn't take much time, and if that does work, you may rule out some potential issues already.
I attempted to make the simulation of a single inlet and no species transport model, then it worked well
When I tried simulate with the species transport model on, I encountered the same problem again...
But the way what is the difference between MRF and sliding mesh? It seems MRF works in steady state, sliding in transient, but the result are not the same?
lml is offline   Reply With Quote

Old   September 6, 2014, 16:20
Default
  #6
lml
New Member
 
Minliang Liu
Join Date: Jul 2014
Posts: 5
Rep Power: 3
lml is on a distinguished road

this is what I got, please help!
lml is offline   Reply With Quote

Old   September 9, 2014, 07:16
Default
  #7
Senior Member
 
Cees Haringa
Join Date: May 2013
Location: Delft
Posts: 265
Rep Power: 6
CeesH is on a distinguished road
The green spot does indeed look odd. But it doesn't seem to extend vertically? Or can we not see the vertical extent at this point?
CeesH 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
ANSA mesh for sliding meshes (pimpleDyFoam yosuu ANSA 2 July 15, 2014 09:29
Using sliding meshes (AMI) without imposing a fixed rotation hakonbar OpenFOAM Running, Solving & CFD 0 April 2, 2013 06:41
CFD of propeller with sliding meshes ivanddd Main CFD Forum 1 April 19, 2011 13:30
sliding meshes Tim Daly FLUENT 3 November 20, 2008 09:20
Empty surface in sliding meshes. Pierre Ricco FLUENT 2 March 14, 2001 17:01


All times are GMT -4. The time now is 09:56.