Free slip vs no slip

Rohan

I have a drop of water which is experiencing a pressure variation from its bottom(flat) surface owing to an acoustic source. (rayleigh wave)

when i define this surface as no-slip and provide the relavant U,V,W vel components at the boundary, the magnitudes of the steady state simulation are much below what i observe experimentally

however, if i define the bottom surface as a free slip boundary and put the u,v,w data into the initialisation file, then the fluid velocity within the droplet matches the experimental values.

Is the latter approach justified?? Please advie. This post is related to " sinusoidal boundary condition"

Thanks