Counting the number of particles in a region

GiorgioDTU · March 27, 2017, 09:06

Hello CFD community,
It is my first post hear however i have been following the forum for quite a while looking for answers. My question has been applied before by several users but it does not seem that i get a clear answer.
So, i have domain which contains two regions which are separated by an internal interface. From one region i am injecting particles using the Lagrangian multiphase. I need to count the number of particles that exist at each region at every time.
I have already tried the boundary sampling but with no luck. Maybe i am doing it wrong so if someone could give clear directions of how to proceed would be great.
Element count does not work since it count the number of cell in the region. As i have understood the most viable procedure is through the boundary sampling.
Please help

Best,
Georgios

Antoni_char · March 27, 2017, 09:09

I have almost the same problem with Giorgio DTU and I have no idea how to solve it.

me3840 · March 27, 2017, 09:42

This question is covered in the user guide. Please read the section on langragian post-processing. You can use the element count report to easily count the number of particles in any region.

GiorgioDTU · March 27, 2017, 12:14

Hello me3840,
Thank you for the quick reply. I guess the suggested solution is in the part Post processing Lagrangian data and the subsection you are referring about is the ''Local instataneous data'' at page 4374 of the user guide(version 11.02). I followed the exact procedure but did get any results. I am attaching photos with the procedure i followed and please correct me if you find something incorrect. The problem is that despite the fact that there are particles already specified in the region with index 2 , the element count does not find any particles there. I am really sorry for the long post and i hope your eye sees something that mine cannot.
Best Regards,
Georgios

Schwob77 · March 30, 2017, 16:24

It seems the region you are trying to separate has a region index of 2.0, right? In this case I would use a range of [1.5,2.5] instead of [2.0, 2.0].

GiorgioDTU · March 30, 2017, 17:24

Hello Schwob77,
You are right. I am trying to count the particles in region 2. I just tried what you suggested but unfortunately didn't work.

Thank you for your interest nevertheless.
Best,
Georgios

March 27, 2017, 09:06	Counting the number of particles in a region	#1
GiorgioDTU New Member Georgios Sartzetakis Join Date: Nov 2016 Posts: 3 Rep Power: 9	Hello CFD community, It is my first post hear however i have been following the forum for quite a while looking for answers. My question has been applied before by several users but it does not seem that i get a clear answer. So, i have domain which contains two regions which are separated by an internal interface. From one region i am injecting particles using the Lagrangian multiphase. I need to count the number of particles that exist at each region at every time. I have already tried the boundary sampling but with no luck. Maybe i am doing it wrong so if someone could give clear directions of how to proceed would be great. Element count does not work since it count the number of cell in the region. As i have understood the most viable procedure is through the boundary sampling. Please help Best, Georgios

March 27, 2017, 09:09	the same problem	#2
Antoni_char New Member Antonis Join Date: Mar 2017 Posts: 5 Rep Power: 9	I have almost the same problem with Giorgio DTU and I have no idea how to solve it.

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March 27, 2017, 09:42		#3
me3840 Senior Member Join Date: Nov 2010 Location: USA Posts: 1,232 Rep Power: 24	This question is covered in the user guide. Please read the section on langragian post-processing. You can use the element count report to easily count the number of particles in any region.

March 30, 2017, 16:24		#5
Schwob77 Member Join Date: Nov 2015 Posts: 38 Rep Power: 10	It seems the region you are trying to separate has a region index of 2.0, right? In this case I would use a range of [1.5,2.5] instead of [2.0, 2.0].

March 30, 2017, 17:24		#6
GiorgioDTU New Member Georgios Sartzetakis Join Date: Nov 2016 Posts: 3 Rep Power: 9	Hello Schwob77, You are right. I am trying to count the particles in region 2. I just tried what you suggested but unfortunately didn't work. Thank you for your interest nevertheless. Best, Georgios