Okshelly wrote:
So: on the side of the car between the wheels in the reference frame of the car there is a strong fluid flow, which is the one deflecting exhausts and dust backwards in that reference.
Said it better than me.DumHed wrote:having read this thread from the beginning, after hearing people talking about how the FEE works, I've finally signed up on F1Technical - because it's getting a bit stupid!
Why is everyone arguing in absolutes?
Obviously in at least some conditions, some of the exhaust will go under the floor and through the diffuser. (High yaw, low exhaust flow, crosswinds?)
Will the small amount of exhaust, after travelling the distance to the diffuser, add any meaningful mass flow or drop of temperature and therefore volume / pressure through the diffuser?
I see no possibility of the majority of the exhaust being sucked under the floor and into the diffuser, as there would be no benefit. Normally the floor is designed to keep low pressure high velocity air underneath - sucking minimal air in from the sides.
To get the diffuser to suck exhaust in from the sides would mean a massive amount of ambient air coming in with it, greatly reducing the effectiveness of the floor and diffuser.
In my opinion, the FEE is creating downforce directly on the front corner of the floor, by blowing very high velocity gas under the small aerofoil section there, and is also creating a virtual skirt by pushing air away from the side of the floor - to prevent it from being sucked in and harming floor / diffuser efficiency.
The exhaust volume and velocity, especially with the extra "blowing" engine mapping techniques carries a lot of energy, and with the near 90° exits, will blow quite wide until high car speeds.
Have a look at the exhaust of a car running on a dyno. Even with a 300-400hp turbo engine and a 75-100mm diameter exhaust exit, quite a strong jet can be seen and felt - usually very visible due to the light fuel smoke caused by rich air fuel ratios.
MY GOD!! HOLY JESUS!! AMEN!! HALLELUJAH BORTHER Imightbewrong!! Preach it!!imightbewrong wrote:From the horse's mouth:
[youtube]http://www.youtube.com/watch?v=PDWFaRVQ ... r_embedded[/youtube]
So, nothing to do with the vertical component of the flow coming off the leading car then?ringo wrote:This is why the F1 car loses downforce when following another car. The speed of the air behind the leading car is higher than still air. This means that the following car will pass through the air at a slower rate. It's all relative.
ringo wrote:Diffuser diffuser.
The diffuser is not always the end game for everything blown.
Now this thread is really good treasure trove of discussion and proof of CFD tests outside of a super computer equiped F1 team or lab.
This conclusion was made months before there was any input from the Team.
It was spot on as well.
What Alison says is no suprise, and this may be why it seemed like i was being arrogant. If you do a sound and measured experiment and you get your results, and then you go and witness in the field real time observations that are in line with yours, you may come across as arrogant if someone with no evidence but their words tells you otherwise. You simply cannot discard what you observed or back down because you can't call upon the big shot inside links.
The speed and the energy is important. The further the exhuast travels the more speed and heat energy it loses. This was the elephant in the room.
For maximum energy to whatever part of the car, the exhaust exit has to be located there for greatest influence.
2.5m down stream isn't going to help much, even it's going to the diffuser.
Blunty:
Put high energy where you want the greatest effect. Simples
TBH It seems to me that uor theory is not what Allison said. He said they DO BLOW THE FLOOR. This thread claimed all the exhaust went out along the sides of the car. Allison said the the R31 blows the "wing profile" at the LEADING EDGE of the floor. That's different from what has been said in this thread.ringo wrote:Diffuser diffuser.
The diffuser is not always the end game for everything blown.
Now this thread is really good treasure trove of discussion and proof of CFD tests outside of a super computer equiped F1 team or lab.
This conclusion was made months before there was any input from the Team.
It was spot on as well.
What Alison says is no suprise, and this may be why it seemed like i was being arrogant. If you do a sound and measured experiment and you get your results, and then you go and witness in the field real time observations that are in line with yours, you may come across as arrogant if someone with no evidence but their words tells you otherwise. You simply cannot discard what you observed or back down because you can't call upon the big shot inside links.
The speed and the energy is important. The further the exhuast travels the more speed and heat energy it loses. This was the elephant in the room.
For maximum energy to whatever part of the car, the exhaust exit has to be located there for greatest influence.
2.5m down stream isn't going to help much, even it's going to the diffuser.
Blunty:
Put high energy where you want the greatest effect. Simples
etc. etc. It's all there pierce.ringo wrote:Where do you get your theory from? which reference?
The exhuast speed is 220m/s it's not 38m/s. Usain Bolt can run over 30m/s.
As to the flow, no human being can simply suggest where it's going. You need years of experience, and even then Willem Toet the aerodynamicist declined to make a guess.
but it's a good thing you bring up this picture.
If the air is going down 90 degrees, then why is there a gurney at the edge of the floor?
We always see these gurney on down-force generating devices and especially when exhaust flow is involved.
Why put the gurney if the gases never get there?
