Time varying diameter of the particles

Dear All,

I am trying to simulate microbial interactions in a waste water treatment plant in which microbes grow over time. As a start I am trying to model sedimentation of very dilute phase with microbes falling under gravity and use fix viscous to include hydrodynamic interactions.

I was wondering if this could be done using existing capabilities of LAMMPS. I am specifying particles of type sphere with finite diameter and density.

As a initial guess, may be something fix that could do: d(t) = d(t-1) + growthrate(t)*t ? or closest fix i could modify?

I would deeply appreciate any pointers/help in this regard.

Kind regards
Prashant

Fix adapt can be used to time-vary the diameter of particles of type atom_style sphere.

Everything else you described seems do-able with the commands you mentioned.

Steve

Thanks steve for the reply,

A follow up question: could I break an atom to 2 if say it exceeds a maximum diameter using some fix or replace atoms ?

Kind regards
Prashant

Thanks steve for the reply,

A follow up question: could I break an atom to 2 if say it exceeds a maximum
diameter using some fix or replace atoms ?

technically, yes, buy you would have to write that fix. i don't think
that any of the existing fixes can be used for that.

axel.

Thanks for the replies Axel.

Another follow up question: If there is a closest fix i could modify for the atom division: i.e. replacing the atom with 2 daughter atoms if say it exceeds a maximum diameter (done using fix adapt)?

I would write the fix myself, i am just looking for a closest starting point.

Thanks again

Kind regards

Prashant

If you’re going to add atoms, you should look at other

fixes that do that, b/c they need to operate at a particular

point in the timestep. See fix deposit or fix pour for examples.

Steve