Complicated air flow in front of a fan

I started this video to show why a cowling around the fan wouldn't help, but as I experimented, things got more interesting.

More about my crazy 1 hp fan: http://woodgears.ca/siren/fan.html

Experiments with the veturi effect: http://woodgears.ca/physics/venturi.html

My other channel: https://www.youtube.com/channel/UC3_AWXcf2K3l9ILVuQe-XwQ