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Old 07-04-2010, 08:06 AM   #23 (permalink)
donee
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Join Date: Jan 2008
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Quote:
Originally Posted by ChazInMT View Post
Sorry, gotta chime in here lest someone read that putting Vortex Generators on your FRONT WINDSHIELD may be good for fuel economy. It's not. It can't be. Plain and simple. If it was, we'd all have them on there now wouldn't we....seriously. Think about it. ENuf Said. I won't even entertain a debate or discussion about it beyond this post.
Hi Chaz...,

Your quote is hardly any kind of reasoned response, ie text that describes your reasoning to support your position. Its a simple opinion , without any thought process described at all. As such its useless.

If you feel my idea is totally worthless, then PLEASE describe why you think this is so. Just saying it is totally insufficient.

I reapeat - The CUBE has a very vertical windshield. The OP needs to put yarn tell-tails on the outside edges of it to see which way the air flows. Its my hypothesis that in the outside upper areas of the windshield he will find air flowing with considerable force in a direction that is well off the line of the air flowing around the car. Its only there where VGs may be applied to good effect. This air has momentum. When it shoots off the windshield sideways, it wont instally conform to the air flow around the car. It will continue to flow in the direction it had on the windshield for a short period of time, and and then bend and rejoin the flow around the car. This phenomena will result in the effective cross-area of the car to be larger than it mechanically is.

Introducing vorticity in the flow along the windshield may help the flow rejoin the flow around the vehicle at the edges of the windshield. The vorticity will rob the air of momentum in its direction of travel. When it flows off the windshield, it will quickly conform the air flow around the car. This will decrease the effective area of disturbed air. And it may reduce drag.

To achieve this, the direction of introduced vorticity may be important. The OP will need to experiment with the angle of the VG from the apparent flow, and numbers of VGs to determine the best effect. My guess is no more than two at each windshield upper corner (four altogeter). It very well may be just one VG in each corner.

I think we all here have been satisfied that VGs do not reduce drag when applied to the rear of a box like vehicle, based on experiments that have been performed and documented on Ecomodder. In such a case, there is simply no flow for the air over the top of a box like vehicle to rejoin. This is how my suggestion is different from previous investigation.
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