Mean velocity measurements were taken by using a precision constant temperature linearized hot-wire anemometer designed for low speed water flows.
The motor armatures are skewed to minimize cogging which is required for low speed tracking.
It vents hot air maintaining case temps and also has hi and low speed settings to vary between barely audible and silent.
The tarmac driveways have low speed bumps with open access through the middle.
In general, low speed rotaries need large tank capacitors, and high speed rotaries need smaller tank capacitors to obtain maximum power throughput.