Hi @Apsys,
Never done this before, would be interesting to try.
I assume for meshing you would want to use the hex-dom parametric meshing method and set the material point to be within the nozzle. Your deflection point should be the bounding box perpendicular to the end of the nozzle and likely a no slip wall condition. You will need to have a sufficient y+ of 30 to 200 for both the internals of the nozzle and the cells perpendicular to the deflection wall. See here for documentation on this.
The walls parallel to the nozzle should be a zero pressure outlet in order to allow the eventual fluid to exit the domain. You would need this to be a multiphase simulation considering that the nozzle outputs water, just remember to set the sub-domain within to be water and the remaining domain to be air. Setting this up will be the hard part however, so look out for where the subdomains are and the relevant phase values.
The bounding box behind the nozzle can just be a simple wall as well. The nozzle of course is no-slip.
Do try it out and see if its possible.
Cheers.
Regards,
Barry