Air Merging at Heat Extractor Vent or Serious Vortices?

[Shepherd777]

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."

[Joris]

The F60 America is a front engined car, so the hot air is there!

[Shepherd777]

Originally Posted by Joris

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.

[Joris]

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.

[serialk11r]

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".

[aerohead]

Originally Posted by Shepherd777

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.

[freebeard]

"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.

[Shepherd777]

Originally Posted by aerohead

*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.

[Shepherd777]

[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!

[Joris]

Originally Posted by Joris

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