[sparta-users] Help on grid issues in particle counting and "Cell type mis-match..." Error

[Rommil E. <rem...@ni...>]

 Hi!

I am trying to do particle counting in 2D around a rectangular barrier of
width 0.001 and height of 0.02. I used a vertical line as my transparent
surface for particle counting. The full input script is at the end of this
email.

It runs well but there seems to be a region around the barrier where there
are no measured particles. For example, using:

create_box          -0.025 0.025 0.0 0.025 -0.05 0.05
create_grid           20 10 1

there are no particle counts for  x = [-0.02, 0.02]. It seems wrong that no
particles are counted even in front of the barrier.

I tried increasing the grid cells to 80 by 40 by 1 and the problematic
region narrows to x = [-0.005, 005].

Is there a way to better measure particle flux near the barrier?

-----
Upon increasing the grid cells further to 100 by 50 by 1, I encountered an
error. The message says:

CELL1 proc 0 icell 451 id 452 iface 3 jcell 551 id 552 marktype 1 jtype 2
ERROR on proc 0: Cell type mis-match when marking on self (../grid.cpp:1245)

May I know how to prevent this?

Thank you so much.

Regards,

*Rommil Emperado*
National Institute of Physics
University of the Philippines


P.S.
I am running SPARTA on Windows 10 via Cygwin, spa_serial and sparta-20Nov20.




INPUT SCRIPT

seed             12345
dimension      2
global            gridcut 0.0 comm/sort yes
boundary        o o p

create_box          -0.025 0.025 0.0 0.025 -0.05 0.05
create_grid           100 50 1
balance_grid         rcb cell

global              nrho 1 fnum 5E-8
species            air.species N2 O2
mixture             air N2 O2 vstream 0.0 0.0 0.0 temp 300.0
fix                    in emit/face air xlo
collide              vss air air.vss

read_surf           data.barrier trans 0 0.0025 0 scale 1 1 1 clip group
mask
read_surf           data.flux trans 0.00500 0 0 scale 1 1 1 invert
transparent group subs

surf_collide       1 specular
surf_modify       mask collide 1

surf_collide       2 transparent
surf_modify       subs collide 2

timestep           1e-6

compute            flux surf subs air n
fix                     average ave/surf subs 1 10000 10000 c_flux[1] ave
one

dump                4 movie all 50 20210209.gif type type pdiam 0.0002 &
                        size 512 512 particle yes gline no 0.01 &
                        surf proc 0.02 zoom 3.5
dump               5 surf subs 10000 20210209.txt f_average

stats                200
stats_style       step cpu np nattempt ncoll nscoll nscollave nscheck

run                  10000