Vortex Generators! on an FD
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Vortex Generators! on an FD
I saw a pic on this site of an fd with vortex generators similar to the evo mrs on the roof and was wondering who sells these and if anyone has pics of an fd with them, if they could post it on this thread. Also what is the optimal placement on FD roof (measurements please).
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If it's to reduce CD, I suspect you'd either need some serious aero modeling SW to simulate or a wind tunnel to know exactly where (and how many) to place to make a difference ... neither of which many of us have handy.
If it's for looks, well, to each their own...
If it's for looks, well, to each their own...
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They help keep flow attached over the hatch and can help reduce the size of the turbulent wake behind the car and therefore reduce pressure drag.
An easy way to see if this is a problem is to do some wool tufting. Tape bits of wool to the back window and go for a drive while getting someone to follow (not too close to disturb the results) and take pictures or a movie. Where they're pointing back and not waiving, the flow's attached, where they start pointing in different directions and fluttering, you have separation. You'd want to place them a bit upstream of this, but unless you're going to put them on the glass it'll be best to just array them along the top of the hatch.
An easy way to see if this is a problem is to do some wool tufting. Tape bits of wool to the back window and go for a drive while getting someone to follow (not too close to disturb the results) and take pictures or a movie. Where they're pointing back and not waiving, the flow's attached, where they start pointing in different directions and fluttering, you have separation. You'd want to place them a bit upstream of this, but unless you're going to put them on the glass it'll be best to just array them along the top of the hatch.
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Black91n/a put it in simple terms. Another way of saying it is that VGs add energy to the airflow helping it "make turns" without it becoming turbulent. This benefits the MR in the way he said and also has the added effect of reducing rear lift because more "good" air gets to the wing. There is an SAE paper written by the Mitsu engineers that developed the VGs, and it's quite an interesting read.
Having owned an Evo with VGs, and currently owning an FD as well as being an automobile aerodynamicist I've certainly considered the question but haven't been able to weasle my FD into the windtunnel yet to try it out My guess is that if done correctly there would be some rear lift reduction though it would likely be minor. And, I'm not so sure that on an FD the drag benefit from the VGs influence on the airflow would offset the drag they themselves cause.
Having owned an Evo with VGs, and currently owning an FD as well as being an automobile aerodynamicist I've certainly considered the question but haven't been able to weasle my FD into the windtunnel yet to try it out
My guess is that if done correctly there would be some rear lift reduction though it would likely be minor. And, I'm not so sure that on an FD the drag benefit from the VGs influence on the airflow would offset the drag they themselves cause.
Black91n/a put it in simple terms. Another way of saying it is that VGs add energy to the airflow helping it "make turns" without it becoming turbulent. This benefits the MR in the way he said and also has the added effect of reducing rear lift because more "good" air gets to the wing. There is an SAE paper written by the Mitsu engineers that developed the VGs, and it's quite an interesting read.
Having owned an Evo with VGs, and currently owning an FD as well as being an automobile aerodynamicist I've certainly considered the question but haven't been able to weasle my FD into the windtunnel yet to try it out My guess is that if done correctly there would be some rear lift reduction though it would likely be minor. And, I'm not so sure that on an FD the drag benefit from the VGs influence on the airflow would offset the drag they themselves cause.
Having owned an Evo with VGs, and currently owning an FD as well as being an automobile aerodynamicist I've certainly considered the question but haven't been able to weasle my FD into the windtunnel yet to try it out
My guess is that if done correctly there would be some rear lift reduction though it would likely be minor. And, I'm not so sure that on an FD the drag benefit from the VGs influence on the airflow would offset the drag they themselves cause.Aero nerds FTW! lol
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Only FD I have seen vortex generators on, IMO only suits the FD if the rest of the car is styled to match.
Only FD I have seen vortex generators on, IMO only suits the FD if the rest of the car is styled to match.
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There's a good article in here about some basic aero testing including adding VG's onto an FC. Since the FD is similairly profiled it should be very applicable to the FD (starts on page 12).
http://www.pmsc.on.ca/bulletin/2005/JulAug%202005.pdf
http://www.pmsc.on.ca/bulletin/2005/JulAug%202005.pdf
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That's a nice, well written article with a good approch outlined for aerodynamically developing a car at a grassroots level. I see nothing I really disagree with there. There is quite a bit more you can do with a splitter above and beyond what he did, but it is a good starting point.
One glaring omission though that is a big hitter for drag and front lift reduction is sealing off your radiator to the opening in the fascia. All air that goes through the fascia should go through the rad otherwise it is just causing unnecessary lift and drag. This can be accomplished with tape, fabricated panels, foam, etc. Most cars, especially older ones don't have much radiator sealing. A side effect is of more air going through the radiator is better cooling, which can lead to reducing the fascia opening, which can lead to even further drag and lift reductions. A win win win situation.
The general lack of sealing from the factory is due to a lot of reasons but ease of manufacture is often high on the list. In a nutshell, on almost all cars, this is low hanging fruit that you can take advantage of. The FD setup is actually pretty nice for OEM, but there are still some lage "ratholes" that can be filled.
My .02 for the day.
One glaring omission though that is a big hitter for drag and front lift reduction is sealing off your radiator to the opening in the fascia. All air that goes through the fascia should go through the rad otherwise it is just causing unnecessary lift and drag. This can be accomplished with tape, fabricated panels, foam, etc. Most cars, especially older ones don't have much radiator sealing. A side effect is of more air going through the radiator is better cooling, which can lead to reducing the fascia opening, which can lead to even further drag and lift reductions. A win win win situation.
The general lack of sealing from the factory is due to a lot of reasons but ease of manufacture is often high on the list. In a nutshell, on almost all cars, this is low hanging fruit that you can take advantage of. The FD setup is actually pretty nice for OEM, but there are still some lage "ratholes" that can be filled.
My .02 for the day.
