Check this out: by emulating the "bumps" on the leading edges of whale fins, the hydrodynamic efficiency of any wing can be improved by up to 100%! This includes hydroturbines, steam turbines, wind turbines, airplane wings, helicopter blades, any kind of a fan, as well as hydrofoils on watercraft and submarines. Major coolness!



http://www.technologyreview.com/Energy/20379/page2/

Hooray.

Actually, this is pretty cool.

Forget such claims.

More than half of the drag of a good wing originates in its finite span. So over 100% gain is impossible.

And for steam turbines: Their overall efficiency (not just the blades) is well over 90%. Where the hell shall they improve by a factor of 2?

The paper only tells wings stall later (= at greater angle of attack) with such tubercles. Similar forms were already known on airplanes (Learjet etc), but they raised the drag.

The tubercles should - if I figure the airflow properly - bring the advantages of older devices together with a normal drag during flight at normal angles of attack, which is already a nice breakthrough.

I read the article a bit differently.

It would appear that they are effective at increasing the efficency of airfoils that operate at low speeds and high angles of attack.

And while airplane wings can do that, that is not their normal operating range. (of course we might see some interesting changes in the design of leading edge slats for operation in that region)

I think the interest is exactly where it should be, in propellers, which do operate at high angles of attack near the root (note the picture of the Turbine blade is of the root looking out toward the tip)

If the projections of the article are correct the design changes could go a long way towards increasing the amount of viable wind power sites since low average wind speeds is what makes a great many potential sites uneconomical.

Arthur

You're both right, Artur and Enthalpy.

The advantage of this design is that it doesn't introduce additional drag at high speeds and normal angles of attack, unlike the traditional vortex generators -- while producing all the benefits (if not more of the benefits.)

It will indeed dramatically boost viability and output of wind turbines, all the while making them quieter. Even for the already-efficient jet turbines on planes or steam turbines in power plants, this could boost the efficiency even higher while reducing the number of blades required (and thus the weight, size, and cost of the turbine.) It has the potential to do absolute wonders for helicopters, allowing them to greatly increase lift while decreasing the speed at which the blades must spin. The added acoustic stealth benefits will be of particular interest to the Pentagon...

In addition, it has the potential to greatly boost the efficiency of fans and AC systems in buildings and cars. It has applications in watercraft as well, anything from submarines to catamarans to jet skies. I wouldn't be surprised to see tubercles on the next generation of oars for Olympic rowing...

Plus, it really is just brilliant in its simplicity as well as its origin. A union of science and engineering, at their best.

Hello all

Can someone say "quiet tubercles computer fans" in the future.

Love to learn more, hydro turbines used in power generation are throttled to constant revolutions.

The greater the energy return by more efficient blades the greater the power output and the lower the cost.