Go Back   EcoModder Forum > EcoModding > Aerodynamics
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 10-25-2014, 10:21 AM   #1 (permalink)
Grand Imperial Poobah
 
Shepherd777's Avatar
 
Join Date: Aug 2011
Location: Newington, CT USA
Posts: 247
Thanks: 31
Thanked 488 Times in 144 Posts
Question Air Merging at Heat Extractor Vent or Serious Vortices?

I posted this image of the brand new Ferrari F60 America in a different thread that was discussing wheel well vents.

My question for all of you backyard aerodynamic gurus is: What effect would such a vent have on aerodynamics?

Would the airflow on the body right behind the tire at the outside of the vent opening become seriously disturbed, as it would have to "jump" to the body of the door?

Or would it merge/blend with the air coming out of the vent and maintain a laminar flow???

What effect would hot air coming out of that vent be if the Ferrari was a front engine vehicle and not a mid-engine car?

I know historically, Ferrari was not interested in aero at all, just horsepower. Now they are of course considered leaders in aero. So it's kinda hard for me to think they would degrade the Cd for mere "styling."


__________________
Bob Sliwa
"Like a Midget at a Urinal, I knew I was gonna have to stay on my toes......."

http://www.airflowtruck.com
  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 10-25-2014, 11:46 AM   #2 (permalink)
EcoModding Apprentice
 
Join Date: May 2014
Location: The Netherlands
Posts: 114

Volvo 360 - '85 Volvo 360

Peugeot - '01 Peugeot 306
Thanks: 47
Thanked 96 Times in 34 Posts
The F60 America is a front engined car, so the hot air is there!
  Reply With Quote
Old 10-25-2014, 12:20 PM   #3 (permalink)
Grand Imperial Poobah
 
Shepherd777's Avatar
 
Join Date: Aug 2011
Location: Newington, CT USA
Posts: 247
Thanks: 31
Thanked 488 Times in 144 Posts
Quote:
Originally Posted by Joris View Post
The F60 America is a front engined car, so the hot air is there!
Is it? I didn't know that. I thought all new Ferrari's were mid-engine.

Anyway, the aero questions still stand.
__________________
Bob Sliwa
"Like a Midget at a Urinal, I knew I was gonna have to stay on my toes......."

http://www.airflowtruck.com
  Reply With Quote
Old 10-25-2014, 12:55 PM   #4 (permalink)
EcoModding Apprentice
 
Join Date: May 2014
Location: The Netherlands
Posts: 114

Volvo 360 - '85 Volvo 360

Peugeot - '01 Peugeot 306
Thanks: 47
Thanked 96 Times in 34 Posts
It is, the F60 America is based on the F12, which has this powerplant in the front.



Looking at this picture, I think that the vents on the F60 are not used to get rid of the hot air. But are only there to vent the wheelwells.
  Reply With Quote
The Following User Says Thank You to Joris For This Useful Post:
Shepherd777 (10-25-2014)
Old 10-25-2014, 01:55 PM   #5 (permalink)
Master EcoModder
 
Join Date: Jan 2012
Location: United States
Posts: 1,756

spyder2 - '00 Toyota MR2 Spyder
Thanks: 104
Thanked 407 Times in 312 Posts
Wheel wells are a black art, I would imagine they've figured out how to make those vents do something useful that is impossible to just "eyeball".
  Reply With Quote
Old 10-25-2014, 02:21 PM   #6 (permalink)
Master EcoModder
 
aerohead's Avatar
 
Join Date: Jan 2008
Location: Sanger,Texas,U.S.A.
Posts: 15,861
Thanks: 23,922
Thanked 7,207 Times in 4,640 Posts
effect

Quote:
Originally Posted by Shepherd777 View Post
I posted this image of the brand new Ferrari F60 America in a different thread that was discussing wheel well vents.

My question for all of you backyard aerodynamic gurus is: What effect would such a vent have on aerodynamics?

Would the airflow on the body right behind the tire at the outside of the vent opening become seriously disturbed, as it would have to "jump" to the body of the door?

Or would it merge/blend with the air coming out of the vent and maintain a laminar flow???

What effect would hot air coming out of that vent be if the Ferrari was a front engine vehicle and not a mid-engine car?

I know historically, Ferrari was not interested in aero at all, just horsepower. Now they are of course considered leaders in aero. So it's kinda hard for me to think they would degrade the Cd for mere "styling."

*I don't know the answer.
*Here are some thoughts:
# It's a supercar,so if the vent has anything to do with engine cooling,it is under the heat flux of full power (maximum airflow at all times)
# If sealed,the vent is like the open bed of a pickup truck,tacked on on both sides.
# The air cannot flow over that without vorticity and turbulence
# Since there is 'body' behind it,we CAN get reattachment,creating a locked-vortex inside the well.
# If optimized,these extractors COULD hold the cooling system drag to the 2% maximum as Hucho discusses.(And Korff)
# Since its cooling flow,it's not necessarily robbing critical air from the rest of the forebody.
# Since the half-ducts are diverging,it might be evidence that Ferrari optimized them to blend the exhausting flow into the surrounding side flow at the same velocity,which would mitigate turbulence where the two streams combine.Dr.Alberto Morelli did this in Pinifarina's wind tunnel with the 1976-78 CNR 'banana' car.Ferrari will spend 100-hours on a winglet,they'd probably be willing to spend equal time on a vent.
# And bringing the air out the sides probably reduces firewall and floorboard heating,leading to a more comfortable cabin.
# And in the event of a cooling system breach,you don't have coolant hitting the windshield,which could momentarily blind the driver.
# For fuel economy,the vents would be active,morphing (Gill slits) with heat load,always presenting the minimum disturbance as a function of road load.
__________________
Photobucket album: http://s1271.photobucket.com/albums/jj622/aerohead2/
  Reply With Quote
The Following User Says Thank You to aerohead For This Useful Post:
Shepherd777 (10-25-2014)
Old 10-25-2014, 02:57 PM   #7 (permalink)
Master EcoModder
 
freebeard's Avatar
 
Join Date: Aug 2012
Location: northwest of normal
Posts: 27,562
Thanks: 7,738
Thanked 8,554 Times in 7,041 Posts
Quote:
"Like a Midget at a Urinal, I knew I was gonna have to stay on my toes......."
Haven't seen that tag line in a while. Usual disclamer: I don't know what I'm talking about, but that never stopped me before.

The raised contour through the middle of the door would split the exhausted air into two flows. The upper one may very wll be aimed at the turbulence behind the mirror.

To extract work from the waste heat would require a Coanda nozzle, IMHO.

  Reply With Quote
The Following 2 Users Say Thank You to freebeard For This Useful Post:
aerohead (10-27-2014), Shepherd777 (10-25-2014)
Old 10-25-2014, 05:19 PM   #8 (permalink)
Grand Imperial Poobah
 
Shepherd777's Avatar
 
Join Date: Aug 2011
Location: Newington, CT USA
Posts: 247
Thanks: 31
Thanked 488 Times in 144 Posts
Quote:
Originally Posted by aerohead View Post
*I don't know the answer.
*Here are some thoughts:
# It's a supercar,so if the vent has anything to do with engine cooling,it is under the heat flux of full power (maximum airflow at all times)
# If sealed,the vent is like the open bed of a pickup truck,tacked on on both sides.
# The air cannot flow over that without vorticity and turbulence
# Since there is 'body' behind it,we CAN get reattachment,creating a locked-vortex inside the well.
# If optimized,these extractors COULD hold the cooling system drag to the 2% maximum as Hucho discusses.(And Korff)
# Since its cooling flow,it's not necessarily robbing critical air from the rest of the forebody.
# Since the half-ducts are diverging,it might be evidence that Ferrari optimized them to blend the exhausting flow into the surrounding side flow at the same velocity,which would mitigate turbulence where the two streams combine.Dr.Alberto Morelli did this in Pinifarina's wind tunnel with the 1976-78 CNR 'banana' car.Ferrari will spend 100-hours on a winglet,they'd probably be willing to spend equal time on a vent.
# And bringing the air out the sides probably reduces firewall and floorboard heating,leading to a more comfortable cabin.
# And in the event of a cooling system breach,you don't have coolant hitting the windshield,which could momentarily blind the driver.
# For fuel economy,the vents would be active,morphing (Gill slits) with heat load,always presenting the minimum disturbance as a function of road load.
Thanks Aerohead. I'm researching much of your references. I sent you a PM.
__________________
Bob Sliwa
"Like a Midget at a Urinal, I knew I was gonna have to stay on my toes......."

http://www.airflowtruck.com
  Reply With Quote
Old 10-25-2014, 05:22 PM   #9 (permalink)
Grand Imperial Poobah
 
Shepherd777's Avatar
 
Join Date: Aug 2011
Location: Newington, CT USA
Posts: 247
Thanks: 31
Thanked 488 Times in 144 Posts
[QUOTE=freebeard;451861]
The raised contour through the middle of the door would split the exhausted air into two flows. The upper one may very well be aimed at the turbulence behind the mirror.

Hi Freebeard - Your quote above is a great observation. Now that you mention it, one can plainly see how that upper panel diverts airflow to behind that mirror. Excellent!
__________________
Bob Sliwa
"Like a Midget at a Urinal, I knew I was gonna have to stay on my toes......."

http://www.airflowtruck.com
  Reply With Quote
Old 10-25-2014, 05:37 PM   #10 (permalink)
EcoModding Apprentice
 
Join Date: May 2014
Location: The Netherlands
Posts: 114

Volvo 360 - '85 Volvo 360

Peugeot - '01 Peugeot 306
Thanks: 47
Thanked 96 Times in 34 Posts
Quote:
Originally Posted by Joris View Post
It is, the F60 America is based on the F12, which has this powerplant in the front.

Picture

Looking at this picture, I think that the vents on the F60 are not used to get rid of the hot air. But are only there to vent the wheelwells.
I found another picture of the car, which clearly shows that there are no vents in the wheelwell. So they must be for extracting heat from the enginebay.

http://www.carblog.co.za/wp-content/...00484914_h.jpg

  Reply With Quote
The Following User Says Thank You to Joris For This Useful Post:
aerohead (10-27-2014)
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com