Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.
Particle Tracing Release Time Bug
Posted Mar 29, 2017, 2:48 p.m. EDT Charged Particle Tracing, Particle Tracing for Fluid Flow Version 5.2a 2 Replies
Please login with a confirmed email address before reporting spam
Hello,
I am using the mathematical particle tracing module to release particles with the Release from Grid node. I want to model those particles with a linear elastic particle-particle interaction and have used the appropriate node.
If I release 2 particles with the above setup, the particles behave as expected. This can be seen in the v1.mph file I have included.
Now, I actually want to release more particles into the domain at a later time point in the study. So, I added another time to the Release Times field in the Release from Grid subnode. So I should release 2 particles first, then 2 more later. This is shown in the v2.mph file I have included.
However, when the second release time is added, the behavior of the first 2 particles is changed and incorrect. It is almost as if the 2 non-existant particles which haven't been released yet are affecting the interaction forces between the 2 particles that have already been released.
I'm not sure what to do about this, any help is greatly appreciated!
I am using the mathematical particle tracing module to release particles with the Release from Grid node. I want to model those particles with a linear elastic particle-particle interaction and have used the appropriate node.
If I release 2 particles with the above setup, the particles behave as expected. This can be seen in the v1.mph file I have included.
Now, I actually want to release more particles into the domain at a later time point in the study. So, I added another time to the Release Times field in the Release from Grid subnode. So I should release 2 particles first, then 2 more later. This is shown in the v2.mph file I have included.
However, when the second release time is added, the behavior of the first 2 particles is changed and incorrect. It is almost as if the 2 non-existant particles which haven't been released yet are affecting the interaction forces between the 2 particles that have already been released.
I'm not sure what to do about this, any help is greatly appreciated!
Attachments:
2 Replies Last Post Mar 29, 2017, 4:17 p.m. EDT
Please login with a confirmed email address before reporting spam
Posted:
7 years ago
Hi Zachary, this is a bug. The particles which have not yet been released act like they are located at the point (0, 0). This will be fixed in V5.3 which is due to be released soon:
www.comsol.com/events/webinar/Introducing-COMSOL-Multiphysics-and-COMSOL-Server-53-28982
In the mean time, there is a workaround, you can change the value of the Spring constant to:
0.1[N/m]*(particlestatus==1)
which means that the force will only act on particles which have been released (and thus have a particlestatus variable set to 1).
Dan
www.comsol.com/events/webinar/Introducing-COMSOL-Multiphysics-and-COMSOL-Server-53-28982
In the mean time, there is a workaround, you can change the value of the Spring constant to:
0.1[N/m]*(particlestatus==1)
which means that the force will only act on particles which have been released (and thus have a particlestatus variable set to 1).
Dan
Please login with a confirmed email address before reporting spam
Posted:
7 years ago
Dan,
Thanks so much for the fix, I didn't think to try that.
Thanks so much for the fix, I didn't think to try that.