So first step to work out the mass of air moving at different speeds

Using a 20cm diameter tube

Air has a known density (around 1.23 kg/m3 at sea level)

Power = 0.5 x Area x Air Density x Velocity3

Area = 0.125664 m2

1m/s = 0.5 x 0.125664 x 1.23 x 1^3 =0.07728 Watts

5m/s = 0.5 x 0.125664 x 1.23 x 5^3 = 9.66042 Watts

10m/s = 0.5 x 0.125664 x 1.23 x 10^3 = 77.28336 Watts

15m/s = 0.5 x 0.125664 x 1.23 x 15^3 = 260.83134 Watts

20m/s = 0.5 x 0.125664 x 1.23 x 20^3 = 618.266 Watts

25m/s = 0.5 x 0.125664 x 1.23 x 25^3 = 1207.5525 Watts

30m/s = 0.5 x 0.125664 x 1.23 x 30^3 = 2086.65 Watts

Wow unless i have made a mistake with the maths this looks too good to be true.

OK i need to look at efficiencies of the generator/ turbine and tube flow but even is i get 25% efficiency this will work.

Advantages so far

Tesla turbine very efficient, runs at very high RPM making the generator much more efficient.

Only tubes can be seen

There's nothing stopping multiple tubes being added to increase air flow for instance 5 inlet tube and 5 outlet tubes would yield as follows

Area = 0.62832 m2

1m/s = 0.5 x 0.62832 x 1.23 x 1^3 =0.3864168 Watts

5m/s = 0.5 x 0.62832 x 1.23 x 5^3 = 48.3021 Watts

10m/s = 0.5 x 0.62832 x 1.23 x 10^3 = 386.4168 Watts

15m/s = 0.5 x 0.62832 x 1.23 x 15^3 = 1304.1567 Watts

20m/s = 0.5 x 0.62832 x 1.23 x 20^3 = 3091.3344 Watts

25m/s = 0.5 x 0.62832 x 1.23 x 25^3 = 6037.7625 Watts

30m/s = 0.5 x 0.62832 x 1.23 x 30^3 = 10433.2536 Watts

1m/s = 2.2369 MPH

5m/s = 11.18468 MPH

10m/s = 22.3693 MPH

15m/s = 33.5540 MPH

20m/s = 44.7387 MPH

25m/s = 55.9234 MPH

30m/s = 67.1080 MPH

Regarding the tesla turbine

"With proper use of the analytical results, the rotor efficiency using laminar flow can be very high, even above 95%. However, in order to attain high rotor efficiency, the flowrate number must be made small which means high rotor efficiency is achieved at the expense of using a large number of disks and hence a physically larger rotor."