I was trying to figure out what was wrong with my Link case (I just figured it out, it has nothing to do with this…) and my first thought was that it looked like I lost a bunch of particles due to the initial transient so then the spout was just too strong. I do have bc.po_no_par_out = 1 set. I put a Lagrangian::GeneralProperty::Sum monitor on ones over the “full-domain” region to sum the particles, the result vs time is below. I’m losing some, but not in bunches like as if no_par_out wasn’t working correctly. Do you think my particles are just too soft and some are getting squished through the wall and deleted?
You can test if the bc.po_no_par_out flag is working by setting up the simple pseudo-1D problem:
- domain is periodic in x and z directions
- pressure inflow at y-high and pressure outflow at y-low
- gravity acting in the negative y direction
- initialize the domain with a few particles and let them settle under gravity
If the particles all ‘fall out’ then the flag is not working as expected and we’ll need to investigate.
You can test the setup in general by switching the pressure outflow at y-low with a mass inflow with zero-fluid velocity. This will ‘fake’ a wall along the bottom of the domain extent the same way the flag should impose a wall.
I ran a simple test like you suggest: bench05 size008 with gravity sign flipped, so all the particles rush to the top.
I added the same monitor and bc.po_no_par_out = 1. The initial particle count and final particle count match, Np = 7776. so the flag is working as expected.
Back in the Link bed (case B1), I bumped the spring constant up from 43 kN/m to 170 kN/m (halved the collision duration). I expected to see it lose fewer particles, but it’s actually losing more particles (red line, still running). Curious.
