Читать книгу Wind Energy Handbook - Michael Barton Graham - Страница 64

The torque on an annulus of radius r and radial width δr (ignoring a′ as actuator disc theory ignores rotation) is

(3.37)

The radial distribution of power is

(3.38)

and, therefore, the total power is

(3.39)

Power coefficient:

(3.40)

Again, a result that is identical to that predicted by the simple momentum theory.

What is particularly interesting is that the residual rotational flow in the wake makes no apparent reduction in the efficiency of the power extraction.