I found another example of biomimicry which improves the flow of air: wind turbines inspired by whales.
The flippers of the humpback whales have non-smooth leading edges which contradict the smooth leading edges of all our man-made aerodynamic blades. The large, irregular looking bumps across the leading edges are called tubercules and maintain even channels of fast-moving water when it passes them. If smooth flippers would be used, the water flowing over those would break up into myriad turbulent vortices.
Wind tunnel tests of model humpback flippers with and without those tubercules across the leading edge proved that the tubercules were responsible for a reduction of 32% in drag, of 8% in lift and an increase of 40% in the angle of attack.
A company called WhalePower uses this technology for their fans and turbine blades. Their motto is also a nod to nature with the ‘A Million Years of Field Tests.’-part, which can also be read at the bottom of their website.
Formula Group T Aerodynamics 
I’ve read on their site that Whalepower boasts a 40 % increase at low speeds compared to a smooth blade design.
There are thousands of wind turbines with a smooth blade design in the world today. Would it be worth the investment to retrofit them with these tubercules?
Is this the same effect as the dimples in a golf ball?
Aren’t this kind of blades much harder to produce? What’s the drawback of this design? Because I never saw something like that in real life, can you give an example?