Is there some functions available in lammps to create and maintain a bubble within the water box?

LAMMPS
1

Hi. Everyone.
I want to create and maintain a bubble within a water box.
I know that tclBC and tclForce within namd can do this. However, the available force fields is limited within NAMD.

Hence, is there some similar function within lammps ?

2

The equivalent for that in LAMMPS is fix addforce which can have fixed or variable (global and per-atom) values as forces.

An simpler approach may be using fix indent with a variable radius for a spherical indenter.