Turbulators?
 

I think that's what they're called, the spike-like things on the roof of the car where it starts to curve for the back window, seen them mainly on Mitsubishi. Question is: DO THEY REALLY HELP?
Do they make the car more aerodynamic, apparently they're supposed to "trip" the airflow, I think by decreasing the size (or something) of the vortexes that occur at the end of the car. Any thoughts, advice, data?

Here is a picture of what I'm talking about. The 8 spike/bumps on the side of the antenna.
http://www.seriouswheels.com/pics-20...A-1024x768.jpg

They work in conjunction with that wing. Those delta-vortex generators basically bend the air coming over the roof to interact more with the wing. With no wing they serve no purpose in that application. Its about down-force, not drag reduction. In fact they add drag.

they do what they claim to "help keep the airflow attached" but test after test on here has proven that they don't help the aero behind the car. i do have a friend that placed them under his car about 6 inches from the front of his belly pan and it reduced the "floatiness" of the car when dealing with crosswinds (and passing semi-trucks, when dealing with the air deflected to the side by the flat front)

On the Evo, they reduce the drag coefficient by .006.

Hi Capn..,

Those delta shaped things are VORTEX GENERATORS. A TURBULATOR is a thin layer of material with a zig-zag cut at the leading and trailing edge.

Vortex Generators help air flow around a sharp corner, but at the expense of some drag. The overall drag , properly design, is not that much different.

A turbulator introduces turbulence into the air flow. There purpose of turbulators is to prevent flow momentum causing the air to continue in its present direction, but to tumble and conform to to the shape of the airframe.

You have seen an application of the Vortex Generator, on the EVO to get the air to flow over the rear wing.

Turbulators are used on sail plane wings to prevent the air from going higher over the wing than the wing is, resulting in flow seperation.

On this site we have discovered that when you have a steep windshield angle, some small benefit can be had by putting a turbulator on the upper 1/3 of the A-pillar. Thus the air flowing diagonally across the windshield conforms to the flow down the side of the car, quicker. This is because with a steep windshield, some of the air in the outside corners is going sideways as it hits the upper 1/3 of the A-pillar. And it has momentum to shoot out sideways larger than the car actually is. By exhausting the energy asociated with this momentum, the air will combine nicely with the flow down the side of the car.

Thanks for the explanation!
I was looking at another site for car aerodynamics and it called those things turbulators.

So these are turbulators-http://i17.photobucket.com/albums/b53/edbso/zig-zag.jpg

Hi capn..,

Yes, those are turbulators.

OP here is all the info on the Evo vortex generators.
http://www.mitsubishi-motors.com/cor...004/16E_03.pdf

Yeah, old thread, but I use the search function ;)

Anyone know if the person from the car pictured bought or made that strip?

there are sewing siccors that cut like that.......my mom had some yrs ago.

So is that just paper glued on there?

Whether they bought it or made it, it is a gross misapplication of the concept. This tabulator tape is made to help aid the flight surfaces on Gliders. They are meant for laminar flow situations and have no business being anywhere on a car which is in a completely turbulent flow aero state.

This would be like going to the beach before a hurricane strikes and putting 20 softball sized stones in the surf zone, then declaring your portion of the beach will be protected from the oncoming 15 foot waves, the stones will break up the flow.

I just wanted to correct something of a misstatement made earlier. The vortex generators are not, necessarily, designed to work only with the rear airfoil on the EVO. By decreasing the flow separation across the rear window, vortex generators allow more "clean" air to hit the airfoil (allowing the airfoil to more effectively produce downforce). Even if the airfoil weren't there, the car would benefit from the reduction in flow separation.

I'd like to correct the misstatement about the misstatement being a misstatement. The vortex generators (VG's) were indeed placed to make the airfoil more effective, and it is highly unlikely they would provide an iota of benefit in reducing total drag on the car. Very little to no valid information has ever been put up about VG's being beneficial. How do you even know there is a reduction in flow separation?

Everything written about vortex generators has been anecdotal. You're welcome to do some A-B-A testing and let us all look at the results and see what benefit there is. Don’t just come in here guessing that they’ll improve things because it seems to make sense what the people who want to sell you VG’s are saying.

Also, flow separation or attachment is not the magic bullet that automatically gives you better aerodynamic efficiency. Keeping flow attached on a lousy shape will probably actually hurt you. The other thing to bear in mind, is that interactions of the air flowing in from the sides and top over the various shaped automobiles is very complex. Slight changes could have dramatic results by creating larger vortices than those created prior to any change. Slight changes will rarely result in improvements on any modern vehicle due to the advances in aerodynamics that automakers have achieved. Obvious exceptions to this are grill blocks (I think auto makers have to design the cooling system to be driven up-hill, in Death Valley, fully loaded, going full throttle), mirror deletes, and major changes to a cars aerodesign to make it more closely match the aero template.

I, personally, do not have a wind tunnel with which to test the vortex generators; however, Mitsubishi does, and their techs have done extensive testing and analysis. The Evo is a purpose designed platform, and while it is true that low drag is not necessarily the focus of their designs, they were accounting for it. If, through their wind tunnel testing, they found that the vortex generators created a 1% reduction in Cd, I believe them.

So a team of engineers with a windtunnel were able to eek out 1%......I rest my case. Thanks for helping me make my point.

Now you're just being combative, but if that's what makes you feel better about yourself. :thumbup:

Also, to be fair, the number is closer to 2% (~1.8%). Given that their main focus was not reducing drag, the fact that it has that effect regardless does have interesting implications. Especially for DIYers who have cars of similar designs. If people find this to be a simple way of stabilizing the rear of their cars at freeway speeds while also reducing drag (even if only by a small amount). I know that does not agree with your expert opinion on the matter, but most people value real-world results over expert opinions.

I can understand your obvious concern about companies that market these products of dubious value, but Mitsubishi did not design this as a separate product or gimmick. It was purpose-built and included with the vehicles for sale. They didn't make any extra money on it, and given the nature of the car, it was done as much if not more for performance than for aesthetics.

Go and visit the Unicorns on this one, they are getting lonely.