srd fluid in a cylindrical tube

Hi LAMMPS community,

I am trying to simulate the srd fluid in a cylinder. Using fix srd/wall we can simulate the srd fluid in a rectangular channel, but it can’t do a cylindrical tube.

I have defined my simulation box as a cylindrical region using - region mybox cylinder z 0 0 5 1 49 and later defined a new bigger region - region newbox cylinder z 0 0 7 0 50 to use as the smooth wall**.**
For the integration I am using fix fxwallsrd all wall/region newbox harmonic 20.0 0.0 1.0 for the interaction between tube and fluid and fix fxsrd all srd 1 NULL 1.0 0.25 49894 collision slip for the srd fluid**.**

But the simulation is just getting terminated out. Eventually I am going to simulate a polymer in a tube (smooth or atomistic) with srd fluid as the solvent inside the tube. Could anyone please suggest me a work around on simulating the srd fluid in a tube. I have attached my script file.

New year wishes and thanks.

in.tube_srd (653 Bytes)

Fix wall/region will not perform SRD-like interactions
between a wall and the SRD particles. So that part of
your model seems inconsistent.


Thanks Steve,

Is there a way around to simulate the srd fluid in a cylindrical tube ?
Do you have any plans to incorporate a tube in fix srd/wall command ? As you know at present it can only do planar walls, but the general case would be a cylindrical nanopore with solvent and macomolecule inside.

Thanks again.

no - I don't think there is a way to do it with the current
code if you want SRD wall/particle interactions with a cylindrical
wall. Someone would have to add that feature to the code.
It's not a high priority for us, since we don't use SRD in that manner.