Wind turbine blade aerodynamic devices

Cyril recently responded to one of my earlier posts below, asking about a recent article on MIT's technology review titled Whale-inspired Wind Turbines that discussed the hydrodynamic 'design' of whale fins - and possible use of these concepts in the design of wind turbine blades. Namely, the article the discussed the irregulatities in the front of the whale's fins (the leading edge) and the use of this to vary the onset of stall in different sections for better control of the fin. It's a pretty good article, with some good concepts, some of which are already used in the wind industry.

As one of the commenters rightly pointed out, these concepts have been used in the aircraft industry for quite some time - particularly in fixed-wing design. As I sat on a recent 737-800 flight pondering this the other day, I noticed that most of the aerodynamic device used on the wing were also used in one way or another in wind turbine blade design. Looking at the picture below, you can see: leading-edge and fowler flaps, vortex generators, spoilers, ailerons, and winglets (or tip extension).


The first aerodynamic device used in wind turbine blade design (that I am aware of) was the vortex generator. Vortex generators were brought in to delay the stall, and often used as a remedy when the power curve wasn't performing as expected. Now, we see the use of: stall-strips (very similar to spoilers) to damp out vibrations; the use of flaps for pitch control (on a concept level anyway); winglets to increase lift; zig-zag tape to increase roughness, delay ing separation; and rotating blade tips to act as an aerodynamic brake.

I'll planning on posting on each of these aerodynamic devices over the next few months, and will be posting up pictures I have taken over the last few years and reference some interesting test data to support it.