exerting a sinusoidal force or deformation on the interface of two fluids in sph mood

hi all; can someone help me for exerting a periodic deformation or force on a line?

i mean i do not want to exert this force/deformation on an atom or box or else.

tanx

hi all; can someone help me for exerting a periodic deformation or force on
a line?

a line of what?

i mean i do not want to exert this force/deformation on an atom or box or
else.

so how should this then impact your simulation, if it is not directly
or indirectly affecting atoms?

axel.