Red Bull RB8 Renault

[marekk]

And can someone please explain, why it's harder to route the gases this way at higher speeds ?

Because the exhaust leaves the the tip at 84 m/s. 200 mm from the tip it is at less than 40-30 m/s. It is hit by a body flow of 40-70 m/s. ASSUMING the exhaust flowing 90 deg to the body air flow, it would change direction by 45 deg. You are never going to make it to the opening down below.

Brian

Except i can't see this 90 deg.
In my view exhaust gases attach to the surface of the mould and leave almost parallel to the flow around the body.

I stay for now with my calculations from last year's FEE thread - about 75m/s with 80mm pipe's diameter - which means basically exhaust is more or less stationary in external's air reference frame (external flows are slowing down in this region), and goes where pressure and vorticity fields want them to go.

Helped with coanda effect around the curved surface below and behind the exhaust mold, could make it to the tunnel - and more so at speed (low pressure field at the rear of the car gains strenght with square of car's speed).

[kilcoo316]

The faster the car goes, the more it is going to blow the exhaust farther back, away from the entrance to the tunnel.

The faster the car goes, the greater the massflow rate (and velocity) of air from alongside the sidepod towards the car centreline will be.

Guess what - that'll mean the exhaust wake is only further transported inboard.


edit to make this clear, the bit below is a general comment unrelated to the above:
The exhaust goes nowhere near the entrance of the tunnel at any time.

[Adrian Newby]

But seriously if you look at Neweby's post, there's clear markings as to where the exhaust is exiting and which way it is initially flowing. Which it directly towards the inside of the rear tyre.
McLaren are obviously doing this, why are we to think RB doesn't have the same intentions?

His whole discussion disregards the actual information we have about flow velocity in that area. The flow leaving the exhaust is very low about 200 mm for the tip. The air flow over the body has high amount of control over the flow direction at that point and by the time you reach the floor the body air flow has complete control.

We have nothing that clearly indicates what the teams intentions are. You get one picture if you exclude air flow realities and another picture in you include actual flows.

Brian

Your "actual information" is something another board member came up with, on his own, about another car, with another engine, and another exhaust system, in the absence of any other airflow, etc, etc. It is a complete joke and you are wanting us to believe it's gospel. Since you are asking us to rely on your numbers, why don't you tell us what your margin of error is?

[Adrian Newby]

I noticed that too - that you didn't read the regs.

Exhaust plume is caught in cross-flow around sidepod and does not go anywhere near the wheel.

Until you understand the reason for the tunnel - and you still don't - you will continue to get this wrong.

[Adrian Newby]

The faster the car goes, the more it is going to blow the exhaust farther back, away from the entrance to the tunnel.

The faster the car goes, the greater the massflow rate (and velocity) of air from alongside the sidepod towards the car centreline will be.

Guess what - that'll mean the exhaust wake is only further transported inboard.

It's funny that you don't remember me trying to make that point to you earlier - page after page after page...

[kilcoo316]

It's funny that you don't remember me trying to make that point to you earlier - page after page after page...

Going less inboard at low speeds =/= going straight backward.

Until you understand the reason for the tunnel - and you still don't - you will continue to get this wrong.

I really hope you are not trying to say that the exhaust plume + the air that goes through the tunnel comprise the entire airflow above the diffuser deck but below the beam wing and inboard of the brake ducts?

[kilcoo316]

Until you understand the reason for the tunnel - and you still don't - you will continue to get this wrong.

I really hope you are not trying to say that the exhaust plume + the air that goes through the tunnel comprise the entire airflow above the diffuser deck but below the beam wing and inboard of the brake ducts?

[Crucial_Xtreme]

I think this picture makes it clear the exhaust is indeed heading towards the floor edge/inside the tyre, at least at low speeds. I would think the burning on the inside towards the engine cover is due to the car sitting still/pitstop, etc.
But you can clearly see the exhaust has been traveling along the edge of the sidepods towards the inside of the rear tyre.

[Adrian Newby]

It's funny that you don't remember me trying to make that point to you earlier - page after page after page...

Going less inboard at low speeds =/= going straight backward.

Still wrong.

It won't go "less inboard", the exhaust will go outward, toward the tire at lower speeds, and be pushed more straight back at higher speeds.

[GrizzleBoy]

I think this picture makes it clear the exhaust is indeed heading towards the floor edge/inside the tyre, at least at low speeds. I would think the burning on the inside towards the engine cover is due to the car sitting still/pitstop, etc.
But you can clearly see the exhaust has been traveling along the edge of the sidepods towards the inside of the rear tyre.

You could also come to the conclusion that the exhaust has just been going everywhere, noted by the burning basically everywhere lol.

[kilcoo316]

Finally!

We can end this farce once and for all.

As is clearly viewable able from the heat damage, the exhaust flows down the ramp at lower speeds and even further inboard at higher speeds.

Now, where does that put it with respect to the rear wheel?







Thank you and good night.

[kilcoo316]

Still wrong.

It won't go "less inboard", the exhaust will go outward, toward the tire at lower speeds, and be pushed more straight back at higher speeds.

The exhaust itself doesn't point outward.

The shroud/duct introduces it with greater cross-flow to ambient. That wouldn't be like that if they intended it to flow outward.

Instead the exhaust itself would point outward.

[GrizzleBoy]

Finally!

We can end this farce once and for all.

As is clearly viewable able from the heat damage, the exhaust flows down the ramp at lower speeds and even further inboard at higher speeds.

Now, where does that put it with respect to the rear wheel?







Thank you and good night.

The picture says nothing about when what exhaust gases go where at whatever speed.

That is your assumation, not a conclusive fact based on the picture.

[kilcoo316]

Where do you even get this stuff???

I need to correct the previous. A portion of the tunnel's flow doesn't even go above the diffuser deck.


So your saying (for there to be no significant crossflow in the region of the exhaust exit) that a part of the tunnel flow and all of the exhaust plume is enough to satisfy the volume flow rate through the section I mentioned (essentially the box between beam wing, diffuser deck and inboard the brake ducts).


If there is significant crossflow, then your exhaust plumes are gonna blow inward.

[Adrian Newby]

You could also come to the conclusion that the exhaust has just been going everywhere, noted by the burning basically everywhere lol.

Burn marks only show the range, not the mean or median, much less particular paths at specific speeds.