How to perform ANSYS Fluent external flow simulation (free-fall on a substrate) for a syringe?

Hello Experts,
I am using ANSYS Fluent for a syringe-based simulation. It is a pressure-driven simulation where pressure is applied at the inlet, and I aim to calculate the flow rate and velocity at the outlet. While the internal flow simulation is working fine, I also want to perform an external flow simulation to observe how the fluid exits the nozzle (needle) and falls onto a substrate.

My goal is to calculate the flow rate and velocity of the fluid in the free channel flow. I have come across numerous simulations focusing on internal flow, but I haven’t found detailed information on the free-fall aspect. I understand that I need to create a box or an environment connected to the needle. However, I am confused about defining the outlets, walls, and the “Fill” option in the design modeler.

Should both the syringe and the box geometries be hollow, and then filled with the fluid domain using the “Fill” tool? Any guidance or suggestions would be greatly appreciated. I am even willing to pay for help if I can achieve the desired simulation.

Thank you!