# Particle tracking problem with MRF

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

 September 20, 2013, 05:47 Particle tracking problem with MRF #1 Member   Jianye Xia Join Date: Mar 2009 Posts: 32 Rep Power: 9 Hi all, I have encountered the problem with particle tracking in a stirred tank simulation with the Multiple Reference Frame method, the setting of my model is like this: Firstly, I use Freeze/Roter (MRF) to get the initial steady state velocity field in the stirred tank reactor, Then, freeze the velocity field and inject the particles at one small boundary (inlet of the stirred tank), one way coupling (particles have no effect on the velcoity of liquid) of these particles was used, I aslo active the expert parameter of 'pt tracks in absolute frame', but the resulted trajectories of each particle showed that it discontinued at the interface between non-rotating zone and rotating zone. Has any body met with this probem of particle tracking with MRF? Any comments and suggestions is appreciated! Jianye

 September 20, 2013, 06:17 #2 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 12,720 Rep Power: 99

 September 20, 2013, 06:53 #3 Member   Jianye Xia Join Date: Mar 2009 Posts: 32 Rep Power: 9 Thanks， Glenn！ I red that， but my problem is not the streamline but particle trajectory. The trajectory disconnected across the station/rotating interface. Jianye

 September 20, 2013, 07:48 #4 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 12,720 Rep Power: 99 Streamline or particle track, the effect is the same. The change in reference frame means tracks do not appear continuous.

September 20, 2013, 08:22
#5
Member

Jianye Xia
Join Date: Mar 2009
Posts: 32
Rep Power: 9
Glenn, can you make it more clear?

Quote:
 To see continuous streamlines plot the variable "Velocity in stationary frame". This is referenced to the stationary frame regardless of whether the frame is rotating or not, so will be continuous. You might need to access this variable using the puzzlingly labelled "..." button
How can I find the "..." button? Does it in the cfx5post.exe GUI?

When I process the particle trakcing results, there is "Res PT for Particle" in the model tree, when I double clicked it, there was no options for selecting "Velocity in stn frame" in the setting panel of "Res PT for Particle".

I have toggle on the expert parameter of "'pt tracks in absolute frame'", that should be mean that the particle will follow the velocity in stationary fram, am I right?

And what does it mean by "To see continuous streamlines plot the variable "Velocity in stationary frame". "?

How did you do that? can you provide more details ? Thanks a lot!

 September 20, 2013, 08:27 #6 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 12,720 Rep Power: 99 The FAQ is referring to CFD-Post. I am not aware of the "pt tracks in absolute frame" expert parameter but I presume it does what it says it does and those tracks should be continuous. Plotting the variable "Velocity in stationary frame" is relevant to streamlines only. This option is not available for particle tracks.

 September 20, 2013, 08:40 It is sure not continuous #7 Member   Jianye Xia Join Date: Mar 2009 Posts: 32 Rep Power: 9 See attached figure: the red arrow point the disconnectied trajectories

 September 21, 2013, 06:18 #8 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 12,720 Rep Power: 99 I am not sure what is happening there. Have you checked your particle termination parameters?

 September 22, 2013, 16:13 #9 Member   Jianye Xia Join Date: Mar 2009 Posts: 32 Rep Power: 9 I have also checked with the termination parameters, but it did also not work! Any other clues?

 Thread Tools Display Modes Linear Mode

 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 OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post peteryuan OpenFOAM Installation 6 August 18, 2013 18:00 hamidciv CFX 1 April 5, 2013 05:12 mohanrao CFX 4 January 23, 2008 04:39 dbdias CFX 0 September 22, 2007 19:26 desperate FLUENT 0 June 22, 2007 12:35

All times are GMT -4. The time now is 09:48.