Some fluid dynamics is intuitive, e.g., the water flow along a pipe, where what goes in one end comes out the other. However, most applications no matter how simple are anything but intuitive, e.g., the drag of a ball moving through air.

CFD Simulation of Flow Around a SphereHighly sensitive to Reynolds Number

How do you know when to trust intuition? When it comes to fluid dynamics, never! The best way to succeed with fluid dynamics is to amass knowledge early. Don't spend time perfecting the form of your design until you have the function nailed.

CFD Simulation of a StadiumExtremely costly if you get it wrong

The electronics industry calls it bread boarding. The business world calls it bootstrapping. I wonder what the equivalent is in the fluid dynamics realm? Maybe the prototype of the prototype. At your disposal is a powerful set of tools, such as Computational Fluid Dynamics, to move you forward, but skip this stage and you run the risk of your intuition leading you down an expensive dead end.