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Recently it has been discovered that turbercles present in fins from whales are actually providing hydrodynamic benefit for them.

As well, it has been proposed that this effect will provide benefit for airplanes.

enter image description here

From my perspective I can see strong difficulties to see this design able to improve current leading edges, as well, is a design working in water, in a lower Reynolds environment.

My question is actually three:

  • What is the aerodyamic (or hydrodynamic) mechanism and benefit that these turbercle provide?
  • How applicable is that to the airplane industry as proposed in several publications? (first thing I see difficulties is the existance of high lift slats and compatibility with these turbercles, probably more applicable to tails).
  • Which are the potential drawbacks of this design?
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  • $\begingroup$ probably an extension of shock bodies, Owls have similar ridges on the leading edge of the flight feathers $\endgroup$ – ratchet freak Feb 22 '15 at 21:28
  • $\begingroup$ relevant wiki page is a stub with a reference to a pdf paper with some discussion about a set of computer simulations. $\endgroup$ – ratchet freak Feb 22 '15 at 21:43
  • $\begingroup$ @ratchetfreak I read that paper prior to the question and it was not conclusive, only addressing one angle of attack and poor investigation of viscid effects. Looks to me very academic. $\endgroup$ – Trebia Project. Feb 22 '15 at 21:48
  • $\begingroup$ @ratchetfreak: Last I checked, owls didn't usually fly at transonic speeds. $\endgroup$ – Sean Apr 11 at 4:18
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No, please, not another revolution of how we build airplanes again!

The linked article mentions two guys who pose as the discoverers of humps on whale flipper leading edges. What precisely have generations of marine biologists overlooked before?

Now to the humps: They produce a 3D flow pattern close to the leading edge which will help the flow to transition to a turbulent boundary layer more quickly. This is helpful at high angle of attack at intermediate Reynolds numbers (around 1 Mio) and will make the whales more maneuverable.

This is not to say that it will help any existing aircraft. Had nature given the whales the opportunity to integrate slats and double-slotted flaps into their flippers, they sure would have done so. This will help much more to increase maximum lift. Also, typical aircraft Reynolds numbers are much higher than those on whale flippers, and there turbulent transition is very quick. Right now, most efforts center on delaying this transition to reduce friction drag.

Swept wings will see a massive drag increase if this sort of leading edge is used.

The "tubercles" are a very specific form of turbulators and optimized for a narrow application. In other words, don't invest in this WhalePower company!

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  • $\begingroup$ Is basically what I guessed. Do you have references of any study or further information for typical aircraft wings? $\endgroup$ – Trebia Project. Feb 22 '15 at 22:56
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    $\begingroup$ @TrebiaProject: That is a very general question. My experience is with gliders and different types of turbulators, less with studies. Look at zig-zag-tape for a comparable way to create a 3D disturbance which helps to trip transition when the pressure gradient is right. $\endgroup$ – Peter Kämpf Feb 23 '15 at 12:28

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