$26 for a Uni-T anemometer will remove all doubt.
I used it to set up the fans in my 2' x 4' tent and found that 2 meters/second is a little more than is needed to make the leaves flutter.
I used it to set up the fans in my 2' x 4' tent and found that 2 meters/second is a little more than is needed to make the leaves flutter.