Renault R31

[zgred]

[Dragonfly]

yes, it's the radiator

Thanks. I followed the topic about the front exhaust and possible configurations under the sidepods, but there were not much pictures with covers removed during the winter tests.

[BreezyRacer]

It's stunning to see all the damage that Heidfeld had to his car during the race. Watching the feed from Speed TV in the USA I never saw that once. The commentators never saw it either and consequently they were pretty harsh about Heidfeld's performance during the race.

Let's hope Heidfeld gets it right in this next race so he can show his true potential. It seemed like, in testing, he was superior to Vitally, though that's just testing to be sure. Not taking anything away from Vitally .. he drove a great race.

[nacho]

I wonder if Nick's trouble getting heat in the tires was a partial reason in qualy like in 2008.

[BreezyRacer]

I wonder if Nick's trouble getting heat in the tires was a partial reason in qualy like in 2008.

I read a report that said his KERS wasn't working in Q1 and separately Michael Schumacher was warned for balking him in Q1. No excuses though, he better make good on this next race.

[manchild]

There is something illogical on Nick's car. Several meters of cable tied up and laid on the floor to bounce around. It is obviously used to hook up car to computers when car is in garage, but logic suggests that they should have fixed a jack in there and have cable waiting in garage. That would mean not just less weight, but also less chance for damage in collisions as this one.

[Formula None]

Photo I took of Heidfeld's damage in Melbourne. This is at post-race scrutineering.

Great picture, thanks for sharing Fil. Do you have any more close ups? Did you have a press pass or was the car just close to the fence?

Breezy, its a shame the press never picked up on this, Heidfeld got a bad wrap. I wonder how much this affected their exhaust's influence, with the turning vane, part of the floor & flip ups removed.

manchild, maybe the cables are actually tubes hooked up to little ports we can't see in the bodywork for measuring pressure or airspeed somewhere near the exhaust outlet. They just look sort of rigid is all, like the tubing used with pitot arrays during testing.

[nipo]

Maybe this has been asked before, or transferred to another thread, but this thread is a good 73 pages I really can't go through them all (sorry)...

So... What does it mean by an "energized airflow"? Just the temperature? Or pressure?
Why is it so beneficial to have this fed into the diffuser vs regular airflow?
Doesn't exhaust flow vary with throttle? If the system works such wonders like it seems to be doing, doesn't it mean that DF is variable and the car tricky to control?

(Forgive me but I have very little knowledge on aero)

[Formula None]

Maybe this has been asked before, or transferred to another thread, but this thread is a good 73 pages I really can't go through them all (sorry)...

So... What does it mean by an "energized airflow"? Just the temperature? Or pressure?
Why is it so beneficial to have this fed into the diffuser vs regular airflow?
Doesn't exhaust flow vary with throttle? If the system works such wonders like it seems to be doing, doesn't it mean that DF is variable and the car tricky to control?

(Forgive me but I have very little knowledge on aero)

Basically they're trying to push out high pressure air that is above & outside of the floor which is trying to escape into the low pressure area under the floor.

Illustration of flow into a diffuser on an un-skirted car:



Its the whole virtual skirt term everyone's been throwing around since the car's debut.

The pressure under the floor is lower closer to the centerline of the floor, compared to at the edges. So they want to increase the width of this low pressure area by trying to block inward flowing high pressure air with the exhaust flow.

Edit: added ref image.

[volarchico]

Maybe this has been asked before, or transferred to another thread, but this thread is a good 73 pages I really can't go through them all (sorry)...

So... What does it mean by an "energized airflow"? Just the temperature? Or pressure?
Why is it so beneficial to have this fed into the diffuser vs regular airflow?
Doesn't exhaust flow vary with throttle? If the system works such wonders like it seems to be doing, doesn't it mean that DF is variable and the car tricky to control?

(Forgive me but I have very little knowledge on aero)

An answer to all your questions and more:
viewtopic.php?f=6&t=9450

Of course, that's 30 pages, so if you didn't have time for 73 pgs of R31, I'm not sure you'll make it through 30 pages of Exhaust Blown Floor.

[bot6]

For the cables on the side of Nick's car, I think there can be two explanations.

1) those cables were ripped out in the accident so they took an array of long ones to "re-plug" the system at the pit stop, and probably stuck the temp stickers then too, to be able to monitor the car and make sure it was not getting dangerous for Nick. No time to custom cut the cables, so they just took default length ones and zip tied them together.

2) for some measurement systems, the length of cable will have an influence on the output signal. This is especially true for temperature gauges or fiber optic systems used to measure deformation in a composite laminate. There are two ways around this: either you calibrate the system for each measurement point with a custom length of cable once it is in place on the car, which can be quite long, difficult and expensive, or you calibrate each measurement gauge in the lab (much easier, and sometimes more precise), then you use default length cable with known properties to plug the whole thing together on the car and tie the excess cable with zip ties.
I have done a lot of non destructive testing of composite parts in aggressive environments and the second solution (default cable length) is usually preferred as it is easier to implement and gives more predictable results.

[nipo]

Thanks for the response guys.

I can understand the basics of lower pressure under the floor, and the virtual skirt concept etc. My main question is what the term "energized airflow" means, as I've seen it quite a few times when this innovation on R31 is technically described.

Energized = hot? low pressure / fast flowing?

Or is it just irrelevant???

[nacho]

On the previous photos it was visible that there is some electronic gear under the radiator, is it the ECU or some KERS stuff or something else?

[shelly]

Basically they're trying to push out high pressure air that is above & outside of the floor which is trying to escape into the low pressure area under the floor.

Its the whole virtual skirt term everyone's been throwing around since the car's debut.

The pressure under the floor is lower closer to the centerline of the floor, compared to at the edges. So they want to increase the width of this low pressure area by trying to block inward flowing high pressure air with the exhaust flow.

Nice picture, from Katz book I suppose.
I may e wrong, but do not think renault want to block external flow from coming in; instead they want to drag more air from the sides into the diffusers.
I think the sealing function of exahusts takes place at the beginning of the sidepod, where the flow tends to escape laterally after first suction peak on the leading edge.
Agree with you that use of exhausts as virtual skirts has a big scope for developement, especially if their shape evolves and becomes longer and thinner

[BreezyRacer]

Thanks for the response guys.

I can understand the basics of lower pressure under the floor, and the virtual skirt concept etc. My main question is what the term "energized airflow" means, as I've seen it quite a few times when this innovation on R31 is technically described.

Energized = hot? low pressure / fast flowing?

Or is it just irrelevant???

Energized airflow is just some term someone (probably in the press) came up with to sound "techie". In short you are restricting airflow under the outer sidepods of car which allows the airflow you want to introduce (from the tea tray area) to move faster, thus more "energized". Velocity is what makes an undertray/diffuser setup work. The faster you get airflow to go under the car the lower the pressure area, the greater the downforce.

This particular design has the distinct benefit of producing low pressures far forward in the chassis, thus centering the undertray downforce more forward in the chassis, thus achieving a better aero balance and most likely more reliable downforce in yaw and pitch as well. seems to work ..