12-17-2015, 04:34 PM
|
#1 (permalink)
|
EcoModding Apprentice
Join Date: May 2011
Location: Oregon
Posts: 106
Thanks: 0
Thanked 26 Times in 22 Posts
|
Pickup truck vortex used on a car?
I was looking at buying a volvo 850 wagon which has a nice boxy rear end. It occurred to me that that back end looks a lot like the back of a pickup cab.
There is that diagram floating around here about pickup aerodynamics, which shows the small wing on the roof and a half tonneau being the best aerodynamically. I imagine (correct me if I'm wrong) it establishes a stable vortex in the pickup bed, and the air just flows over that vortex down to the tonneau cover. I just wondered if we could move this to the back of my volvo (if I buy one).
The wing is easy, just stick it on the roof, projecting out the back. For the "pickup box", why not just get a receiver hitch arrangement and mount a short, wide box there. The vortex would reside in the box, which could also be used sometimes for carrying stuff. One could easily add a curved surface inside the box to make the vortex even more stable.
If doable, this should be a lot easier than adding a trailer with long, sloping sides and top. The box could physically touch the bodywork so there is no gap, unlike a trailer. Also the rear view mirror still works. The back door is accessed buy simply pulling the pin and removing the box from the receiver hitch.
I'm assuming the axis of the vortex is horizontal. Is that correct?
__________________
|
|
|
Today
|
|
|
Other popular topics in this forum...
|
|
|
12-17-2015, 05:41 PM
|
#2 (permalink)
|
EcoModding Lurker
Join Date: Apr 2015
Location: suburbia
Posts: 76
Thanks: 15
Thanked 14 Times in 12 Posts
|
This is very interesting subject with some claiming improvements and others stopping short of calling VGs snake oil. There is an existing three on vortex generators chech it out.
|
|
|
12-17-2015, 06:01 PM
|
#3 (permalink)
|
(:
Join Date: Jan 2008
Location: up north
Posts: 12,762
Thanks: 1,585
Thanked 3,555 Times in 2,218 Posts
|
Yes the axis is horizontal.
While that set-up represents an improvement to pickups, I suspect it wouldn't for the wagon. The wagon is starting out from a better place with the nice clean cut-off. If one is willing to do the work of replicating a truck box, one could just as easily- or even moreso- hang a nice partial or full tail back there.
|
|
|
12-17-2015, 06:41 PM
|
#4 (permalink)
|
Master EcoModder
Join Date: Jan 2008
Location: Sanger,Texas,U.S.A.
Posts: 16,320
Thanks: 24,442
Thanked 7,387 Times in 4,784 Posts
|
wing/box
Here's a rendering of a quasi-commercial setup which combines the wing and box into an aerodynamic boattail/box-cavity/storage container.
It rolls up to the SUV/wagon receiver hitch on four castor'd pogos,which rise and stow into the belly while on the road.
3-4 mpg.
__________________
Photobucket album: http://s1271.photobucket.com/albums/jj622/aerohead2/
|
|
|
The Following 4 Users Say Thank You to aerohead For This Useful Post:
|
|
12-17-2015, 07:33 PM
|
#5 (permalink)
|
T-100 Road Warrior
Join Date: Apr 2008
Location: The Woodlands, TX
Posts: 1,921
Thanks: 3,502
Thanked 1,395 Times in 968 Posts
|
__________________
Dark Aero-The world's first aerodynamic single wheel boat tail!
|
|
|
The Following User Says Thank You to BamZipPow For This Useful Post:
|
|
12-17-2015, 08:13 PM
|
#6 (permalink)
|
EcoModding Lurker
Join Date: Apr 2015
Location: suburbia
Posts: 76
Thanks: 15
Thanked 14 Times in 12 Posts
|
Quote:
Originally Posted by Frank Lee
Yes the axis is horizontal.
While that set-up represents an improvement to pickups, I suspect it wouldn't for the wagon. The wagon is starting out from a better place with the nice clean cut-off. If one is willing to do the work of replicating a truck box, one could just as easily- or even moreso- hang a nice partial or full tail back there.
|
I am seeing improvement on aero optimized hatchback (Prius C) with VGs installed along roof spoiler, so it isn't that you have to start from very bad to see improvements.
|
|
|
12-17-2015, 08:22 PM
|
#7 (permalink)
|
(:
Join Date: Jan 2008
Location: up north
Posts: 12,762
Thanks: 1,585
Thanked 3,555 Times in 2,218 Posts
|
I'm saying the pickup and wagon are two different scenarios; pickup being worse.
|
|
|
12-18-2015, 07:50 AM
|
#8 (permalink)
|
EcoModding Lurker
Join Date: Apr 2015
Location: suburbia
Posts: 76
Thanks: 15
Thanked 14 Times in 12 Posts
|
Vortex generators are the devices for remixing and increasing speed of boundary layer. As such they need to be applied in the place where they improve aero efficiency of existing design, not to alter it as they are really not capable of doing it.
The was a study which used a combination of VG and spoiler an succeeded in completely eliminating trail wake. But as I recall they tried 26 different combinations in wind tunnel, something we can't.
|
|
|
12-18-2015, 11:13 AM
|
#9 (permalink)
|
aero enthusiast
Join Date: Jan 2015
Location: Saskatchewan, Canada
Posts: 92
Thanks: 157
Thanked 67 Times in 41 Posts
|
terms
I think were getting our terms mixed up a little... A truck bed has a recirculation bubble, where a vortex is air spinning off a generator or wing longitudinally... Also horizontal axis, but towards rear.
That's what grays garage tought me anyways. Check out his vids.
Aerohead has done a nice rendering of your idea. Would shift center of gravity back a bit
Good luck
|
|
|
12-18-2015, 01:46 PM
|
#10 (permalink)
|
EcoModding Apprentice
Join Date: May 2011
Location: Oregon
Posts: 106
Thanks: 0
Thanked 26 Times in 22 Posts
|
OK, recirculation bubble. I was not talking about those little vortex generators at all. Sorry for misleading people...
Aerohead has the right idea with his first picture, except that the top of the box is removed and the bubble sits in there, and also there needs to be a wing on top of the roof.
But I get Frank's point too; the devices are to compensate for the pickup being worse off in the first place, and may be pointless to apply to a wagon.
Interestingly, my Ram pickup is rated at 25mpg (highway) while the Volvo I am looking at is probably a bit worse, even though the Ram is a much larger and taller vehicle. I guess engine efficiency has gone up over the years.
__________________
|
|
|
|