CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > FLUENT > Fluent UDF and Scheme Programming

Particle Injection induced from a UDF

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   June 16, 2013, 02:24
Question Particle Injection induced from a UDF
  #1
New Member
 
Petr Jurcicek
Join Date: Feb 2010
Posts: 21
Rep Power: 13
Peter023 is on a distinguished road
Hello FLUENT users,

I'm currently solving a problem about an injection of particles into domain at an arbitrary time during a steady flow simulation with unsteady particle tracking.

A well known way to inject particles is via the particle injection where the start and stop times are defined. The particles are then injected every time step within the defined time interval. If both times are 0, particles are injected only once.

However, I need to be able to inject particles at any time of the simulation at positions and velocities defined by my UDF. One way to do this I found on CDF forum is to inject more particles than I actually need and keep a part of them dormant (inactive, OFF) and activate them when needed. This is, however, a bit inefficient, since FLUENT will still include these particles into the simulation and slow it down.

Is there a better way how to force FLUENT to inject particles (defined by an injection) into simulation at any time I need from a UDF? Or is there a reasonably simple general way how to append or delete particles from an injection I* via a UDF?

Any suggestions will be highly appreciated.

Thank you.

Cheers,
Peter
Peter023 is offline   Reply With Quote

Old   November 22, 2018, 08:05
Default
  #2
New Member
 
Tim Wittmann
Join Date: Nov 2018
Posts: 4
Rep Power: 4
TimW is on a distinguished road
Hello Peter,

I have a similar problem. Did you find a solution? And could you share it with me? (Even if it was quite a while ago.)

Thank you.

Cheers,
Tim
TimW is offline   Reply With Quote

Old   November 24, 2018, 06:38
Default
  #3
Senior Member
 
Join Date: Sep 2017
Posts: 224
Rep Power: 8
obscureed is on a distinguished road
Hi TimW,


Have a look at "MARK_TP(tp,P_FL_REMOVED);" or possibly "MARK_PARTICLE(p,P_FL_REMOVED);" or both -- for example here:
Stop particle trajectory in DPM
Assuming you're using an up-to-date version of Fluent (and, really, this is strongly recommended), the first one that I mentioned (involving tp) is more likely to be current.


You can kill particles before they really exist, in DEFINE_DPM_INJECTION_INIT, for example.



Good luck!
Ed
obscureed is offline   Reply With Quote

Old   November 26, 2018, 03:55
Default
  #4
New Member
 
Tim Wittmann
Join Date: Nov 2018
Posts: 4
Rep Power: 4
TimW is on a distinguished road
Hello Ed,

thank you for your help!

My current solution is to export a txt-file of particles for every timestep and then define a new injection with execute commands.

Do you know which of these approaches is faster?

Regards,
Tim
TimW is offline   Reply With Quote

Reply

Tags
fluent, injection, particle, udf, unsteady

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
Using UDF to alter particle size Tumppi Fluent UDF and Scheme Programming 7 February 28, 2019 08:27
Problem with a simple UDF to calculate cell-averaged particle values kmayank FLUENT 1 January 18, 2011 01:40
Particle Tacking and UDF Häwimeddel FLUENT 1 September 29, 2009 09:56
HELP! HELP! For udf of particle body force!!!! zhaoh FLUENT 0 February 5, 2007 04:10
DPM, UDF, Injection Type Zhang FLUENT 0 June 8, 2005 15:51


All times are GMT -4. The time now is 12:43.