Lagrangian particle tracking: tracking the residence times at low velocities
 

Hello, my simulation has two inlets and multiple outlets and my there is a region in my domain where the particles slow down and speed up upon leaving that region, so I want to characterize the residence times of the particles at low velocities, in other words, I want to know how long my particles spend at those low velocities. Is there a good way to quantify this?

there is a field function called particle residence time which you should be able to show as a scalar on your track streamlines

I have already calculated the particle residence time. What I want to do is find out how much time the particles spend at a range of low velocities. For example, suppose the maximum residence time is 3 seconds and the particles spend 2 seconds at a low velocity and the other 1 second at a high velocity. How do I determine that value of 2 seconds?

i would hope this information can be extracted with an internal table where you use the particle track as the part and add the required field scalars as the data, like residence time, vel.mag etc.

then you might be able to internally histogram that data or certainly export the table as a csv file and do some analysis in excel.

This is perfect, I didn't know about internal tables. Thank you.

Might be an option to set a separate Region (of interest) connected though Interfaces to other (upstream, downstream) Regions and use Boundary Sampling (recording Residence Time on Interfaces) from Lagrangian model, - and then you could report average Residence time on "inlet" (upstream) and "outlet" (downstream) Interfaces and difference between them.

Also some sort of Residence Time over velocity bands can be used - if you filter obtained (Boundary Sampling) data using velocity-based Thresholds .. or something like that.

I should have been clearer in my original post, my domain only has 1 region so no interfaces were created.

You can always split Parts.

I see I will look into it. Thank you.

So I tried the internal table option first and the output of the table produced a [20,000x5] matrix as shown in the image below. My question is, does each row represent 1 of the particles?. The table was set to save every 10 time steps so I got a total of 120 tables. My simulation has a 0.75s physical time and uses 50 inner iterations.

How can I export a table like this?
I mean, I will simulate a DEM simulation, how I'll export a table with the final positions of all particles?

Go to Tools>Tables>right click New Table>XYZ Internal table

Very thanks

Hello again

Do you know if I can transform the result of a dem simulation into a mesh for a CFD simulation?