View Single Post
Old 06-12-2013, 04:14 PM   #9 (permalink)
Master EcoModder
aerohead's Avatar
Join Date: Jan 2008
Location: Sanger,Texas,U.S.A.
Posts: 11,538
Thanks: 18,553
Thanked 6,042 Times in 3,690 Posts
Vortex strakes

Originally Posted by kach22i View Post
I first posted this in the Unicorn Corral because I thought that was were debatable topics were supposed to go. Turns out I was wrong about that somehow, so to gain a wider audience and hopefully discover with other's help the proof that these work as patented, I now re-post it here.

Vortex strake device and method for reducing the aerodynamic drag of ground vehicles Patent Number US7255387 B2
Patent US7255387 - Vortex strake device and method for reducing the aerodynamic drag of ground ... - Google Patents

If I were to think of this as a rain diverter on a roof, such as found over an entry-way I'd say yes, it works.

However we are talking air pressures and vortexes which have a life far from and beyond the moving body.

What say yee?

I found this quote in the forum.

Fences and strakes are used on aircraft, so there might be something to this patent in my opinion.

We also see similar (but not exactly the same) features on more and more racing cars, and they are being regulated by the rules because they work, right?

1. What tests have these devices passed?

2. Where are they being used?

I await your research, and I'll do a little as well when I can get to it.
I'd be inclined to look into Hucho's most current edition (which I do not possess).
In his first English translation,back in his section on commercial vehicles,he gets into some of these type of devices.He seems to dismiss them, as their origins are in aerospace applications which in ground proximity fail to provide results as in free flight.
Vortex generators were designed to allow flow reattachment at steep angles,onto a trailing structure.
Truck vans have nothing behind them to reattach to.
And base pressure on the back of the van is a function of the pressure at the separation point.Perhaps the induced vorticity channels a bit of extra kinetic energy into the wake from a very thick boundary layer present at the back of the van.
It's a good question.
Photobucket album:

Last edited by aerohead; 06-12-2013 at 04:14 PM.. Reason: spelling
  Reply With Quote