Transition test fan

thingiverse

This is a fan designed for Fan Showdown, not as a true contestant but as a fan to test if we can use the smoke machine for some real aerodynamics testing. The blades have a hollow channel through them and little holes on the top side, allowing smoke to pass through them. The smoke is inserted through the funnel, hopefully separating the smoky airflow from clean airflow going to the blades. I'm very doubtful that the smoke will be visible enough, but if it is, this is going to be really cool. There's a good chance we'll be able to see either flow separation (a big band of smoke 'sticking' to the fan blade parallel to the wingspan) or a laminar-turbulent transition (smoke suddenly 'disappearing' partway along the chord). There may be a need for a high-speed camera or maybe some fan RPM reduction to show anything clearly as well.