Hi Nick,

Wow, a real wind tunnel in your workshop. That must be the sign of a serious hobbyist!

Knowing nothing about wind tunnels, I am not sure if this idea would work in the m/s range.
There is a method, similar to the "hot wire anemometer", to measure the flow of air.

Using "King’s Law", to monitor the cooling on two "self heated" transistors. The transistors also allow the monitoring of it's own temperature (built in), and regulate the self heating currents. I have seen a couple of short articles (by: W. Stephen Woodward), with schematics. If this sound interesting I will look for the references.

Thanks for an interesting problem,
-Adam-