Fixed and variable temperature particles

msbentley's picture
Submitted by msbentley on Wed, 09/14/2011 - 11:13

Hi all,

I'm trying to set up a sim with a region of fixed temperature particles at the top and bottom, and particles that have variable temperature in between. The docs suggest I do not include adiabatic particles in the heat/gran fix. So I've set up a lattice of (4200) particles and defined regions as:

region upper block INF INF INF INF ${upper_limit} INF units box
region lower block INF INF INF INF INF ${lower_limit} units box
region middle union 2 upper lower side out

group thermal_group region middle
3000 atoms in group thermal_group

fix heattransfer thermal_group heat/gran 300.

and after some time I set the temperature of the particles not in this group:

set region upper property/peratom Temp 300.0
600 settings made for property/peratom
set region lower property/peratom Temp 400.0
600 settings made for property/peratom

But the temperature of particles in the middle region never change - I guess they are not connected to the other blocks? Is there another way to fix the temperature of a block of particles, but have others change?

Cheers, Mark

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ckloss's picture

ckloss | Wed, 09/14/2011 - 17:02

Hi Mark,

currently heat transfer between particles in the group and particles not in the group is not included. But probably this would be a good idea, to do a model like the one that you describe.

Try to replace the following line in fix_heat_gran.cpp
if (!(mask[i] & groupbit && mask[j] & groupbit)) continue;
with
if (!(mask[i] & groupbit) && !(mask[j] & groupbit)) continue;

let me know how it works out - if yes, I will include that in the next patch

Cheers,
Christoph