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[hardingfv32]

Has it been accepted the the channel after the exhaust outlet meets the rules? Was there a rule specifying a 10-15 deg cone that started at the outlet that the body work could not encroach into.

Brian

[Gridlock]

Has it been accepted the the channel after the exhaust outlet meets the rules? Was there a rule specifying a 10-15 deg cone that started at the outlet that the body work could not encroach into.

Brian

Yes, many times. A 15 degree come is nothing at these sort of lengths. The rule about it being visible is the more applicable one, and that seems fine too (viewed from above).

[hardingfv32]

1) Has anyone ever seem data on what the flow out an exhaust might look like? Some thing about how the exhaust flow expands as it cools.

2) The teams developed these new exhaust rules. It would be logical to think that they know what the exhaust flow cone looks like and that the rules prevent any manipulation of this flow.

Brian

[Owen.C93]

I don't know how a conclusion was reached about the exhaust just because the flow vis seems greener in one area.
The same shade of green is on the front push rod and on the gearbox.

From observation, no conclusion can be drawn from this image.

CFD is the best attempt to get an idea of what the exhaust cut outs are meant to do.

It's true that deposits of flo-vis don't always show low/high pressure areas because it all depends where you put it to begin with. But that shape in front of the rear tyre looks awfully like an exhaust plume. Not that it gives any indication of how strong the flow it of course.

[aral]

Some thing about how the exhaust flow expands as it cools.



Brian

Hot air expands, so cooling exhaust would actually contract. One of the principles of jet propulsion.

[raymondu999]

Maybe he's talking about how the plume is going out in a cone shape, "expanding" in that way rather than expansion due to temperature change?

[ringo]

I don't know how a conclusion was reached about the exhaust just because the flow vis seems greener in one area.
The same shade of green is on the front push rod and on the gearbox.

From observation, no conclusion can be drawn from this image.

CFD is the best attempt to get an idea of what the exhaust cut outs are meant to do.

It's true that deposits of flo-vis don't always show low/high pressure areas because it all depends where you put it to begin with. But that shape in front of the rear tyre looks awfully like an exhaust plume. Not that it gives any indication of how strong the flow it of course.

the rubber clag off the tyres layered onto the floor could inhibit the flow vis movement. The flow vis will find it harder to move on the floor with all that rubber, so i suspect it will back up as the air pushes it.
This is a possible explanation.

[Pup]

I don't know how a conclusion was reached about the exhaust just because the flow vis seems greener in one area.
The same shade of green is on the front push rod and on the gearbox.

From observation, no conclusion can be drawn from this image.

CFD is the best attempt to get an idea of what the exhaust cut outs are meant to do.

We're discussing. I havent seen anyone concluding just yet. Feel free to post your CFD data though.

[Pup]

Maybe he's talking about how the plume is going out in a cone shape, "expanding" in that way rather than expansion due to temperature change?

Yeah, the outline of the flow seems to make a nice parabola. One explanation would be that we're not seeing the shape of a true exhaust plume, but rather what would be happening as the plume hits the floor, and I'd think we'd see an expansion there despite the cooling gasses.

Another explanation is that if what we're seeing is cooked paint, then the paint wouldn't necessarily outline the exhaust itself, but the heated air around it, hence an expanding shape.

[Pup]

I heard some people here saying the exhaust plumes travel as fast as 600-700 km/h at the pipe's exit. Surely, bending that flow some 30-35 degrees in such a short distance would be a bit more complicated ?

I agree. Seems an awfully dramatic diversion. But see my point below about the air around the exhaust being heated. A rapid expansion of that air could explain it perhaps.

[aral]

Maybe he's talking about how the plume is going out in a cone shape, "expanding" in that way rather than expansion due to temperature change?

Possible, but if it is "expanding" in dimensions, it will also be slowing down.

[gray41]

Could the airflow over the top of the bump that the valley is housed in be somehow forcing the air downwards?

The bump is a very precise shape/size?

[raymondu999]

I have a slight issue with this reasoning - albeit not from an aerodynamicist. If the laminar flow (or wherever you got the flow from) was strong enough to deflect the exhaust downwards to that spot; wouldn't it have been better to just let the flow go there by itself rather than losing some momentum by having to face a 10 degree upward stream in the first place?

[Pup]

The exhaust will want to follow the shape beneath due to the coanda effect. The higher the pressure above the better I suppose, but the exhaust isn't being deflected by that air much if at all I wouldn't think. Think of it as a pipe that bends down, only the top half of the pipe is missing yet the airflow still acts for the most part as if it were there.

[gray41]

Surely there will be a sweet spot angle, for all we know they could have tried multiple angles inside the valley at Jerez.