Exhaust Blown Floor - Forward Exhaust Exit

[shelly]

ringo, I am not misunderstanding nor putting things in others' mouths; neither I am changing my point of view, which has been the same throughout this forum.

Nobody is paying the devil's advocate here: if it seems so to you, it's because you are refusing to discuss, and just reject what others say.

Allison says that the fee is used to enhance the vortex on the leading edge of the floor: that's the vortex that comes from the barge board. If the exhaust interact with this strong vortex, then it probably twists with it, and does not shot wide.

If in your geometry the bargeboard does not produce such a vortex , it would be impossible tpo see such an effect even of the simulation was performed with adequate methods and resources.

[ringo]

The simmulation shows the vortex.

Vortex formation is very dependent on the shape that the air is interacting with.

I did 2 sims, both with different leading edge shapes. 1 sim was used in the earlier stages of the thread, and the other later down.
The first sim the speed was too low, the second was much more accurate but did not have the exact same profile.
These things are not easy for 1 person to do, i don't have a research team.

But what i do know as a fact, is that in both cases, vortex and no vortex, the gases do not go under the floor.

Renault were also experimenting with the pipe angle and the height over the floor.

In winter testing they had the pipe like my first sim; halfway between the top and bottom of the floor leading edge.
This was why they put the temperature stickers on the control arms earlier.

They soon learnt that the floor works better with the pipe blowing under the edge.
I made that adjustment to my design as well.
That was the only difference as i changed the leading edge of the floor.

All other things are consistent with the CFD.
None of this went over my head. I suggested that the edges of the floor were being blown, then it was shot down because "other cars have the gurneys in the same spot".
So Shelly all of that was in consideration when i said it blew wide of the floor.
In fact the floor edge would not work as well if the exhuast didn't take as a wide a path, as the flow would be compromised running too close against floor.

[strad]

Isn't this vortex exactly what would create the sealing effect?

[hardingfv32]

Ringo

"But what i do know as a fact, is that in both cases, vortex and no vortex, the gases do not go under the floor."

This is another broad statement. May we assume you mean the gases do not flow under the complete floor length? Does not some exhaust have to flow under the front outer corner of the floor to form the vortex?

Brian

[hardingfv32]

strad

"Isn't this vortex exactly what would create the sealing effect?"

Allison makes no mention of sealing the floor. He speaks of utilizing the center low pressure zone of the vortex. I would assume the goal is to reduce the pressure under the floor. Sealing would imply preventing high pressure form entering under the floor.

Do we in fact have any research that shows vortices can have a sealing type effect on any part of a F1 car?

Brian

[ringo]

Why do we have to think so one tracked?
We are too dependent on being spoon fed.
Come on man.

There are three things going on with this system and Allison said 1 of 3.

He's not going to spill the beans, the season is still on.

Just as there was evidence from CFD to suggest that the front of the floor was being blown, the same evidence suggest that 2 other things are happening.

The evidence is there, and so are the numbers, but i purposely withheld the numbers to prollong the thread.

[MIKEY_!]

I would have said that vortex would draw the exhaust flow under the floor to some extent.

Edit: could the floor be made to flex downward at the outer edges to give a similar sealing effect.

[Just_a_fan]

But what i do know as a fact, is that in both cases, vortex and no vortex, the gases do not go under the floor.

On your model. Your sim only gives answers about your model. It can not categorically exclude other results in other systems.

You need to model several different designs and conditions, not least an exact replica of the Renault, in order to be able to state that you know what is happening exactly.

[hardingfv32]

What does Allison have to hide? Who wants to or has the time to copy this less than successful system at this point in time?

I do not recall anywhere in this thread (maybe the whole forum?) that a vortex was being formed to harvest the low pressure zone at its center.

To be precise what are the three purposes of FEE system as you see it? Use a simple and clear description.

Brian

[Pierce89]

Saying that the exhaust flow is always under the floor is a broad statement. Does it go under the complete length and width of the floor or just one corner at the front?

Allison said that the low pressure zone of a vortex was the goal. This would seem to be accomplished by flowing across and under the front outer corner of the floor.

Brian

I didn't mean the exhaust necessarily traveled the full length of the floor. i just don't think it went way out to the sides like people claimed on here.

Well it varies with speed. It blows wide at low speeds obviously. And those snap shots from valencia are proof.

of course it blows wide at very low speeds, but in F1 cars most corners are taken in excess 120kmh
giving a signifigant rearward vector. Also, for a vortex to lower the pressure under the floor in any meaningful way as Allison says it does, it will have to pass under the floor for at least some distance.

[Pierce89]

Ringo

"But what i do know as a fact, is that in both cases, vortex and no vortex, the gases do not go under the floor."

This is another broad statement. May we assume you mean the gases do not flow under the complete floor length? Does not some exhaust have to flow under the front outer corner of the floor to form the vortex?

Brian

sorry I also meant to add this quote in with my last post as what Hardingfv32 says exactly what I mean when I said the vortex would have to pass under the floor to lower the pressure under the floor.

[hardingfv32]

The center of the vortex is where the low pressure is found. I would not think routing the complete vortex under the floor is how it is done.

It would seem that to harvest the low pressure of a vortex that you would have to place the center of the vortex just below the edge of the floor. What would this do to vortex shape/flow? Are there vortexes that are not helix in shape?

Brian

[strad]

I know no one pays any attention to what I say but what the hell...
If you go back and look at the old ground effects cars, you see that what made them work was sealing the edges with skirts so the diffuser could work better..so too with today's attempts to extract the most from the diffuser it only makes sense to me that if you feed these exhaust gasses from the front edge outward,,,as we know they do, then as they bend backwards they flood the edge and form a skirt of charged moving air,,,but hey what do I know? I know that even to them it's a "black art" and they aren't even totally sure what the effects of the things they're doing are. They can't do full scale rolling roadbed wind tunnel testing...they can't even get their measurements correct from the scale one..they're guessing and so are we.

[ringo]

Ringo

"But what i do know as a fact, is that in both cases, vortex and no vortex, the gases do not go under the floor."

This is another broad statement. May we assume you mean the gases do not flow under the complete floor length? Does not some exhaust have to flow under the front outer corner of the floor to form the vortex?

Brian

sorry I also meant to add this quote in with my last post as what Hardingfv32 says exactly what I mean when I said the vortex would have to pass under the floor to lower the pressure under the floor.

No.

Does a wing tip vortex pass under any floor?

I'll just stand by for now and watch the techno babble unforld. I think there are enough facts already in the thread that readers can draw from.

[ringo]

I know no one pays any attention to what I say but what the hell...
If you go back and look at the old ground effects cars, you see that what made them work was sealing the edges with skirts so the diffuser could work better..so too with today's attempts to extract the most from the diffuser it only makes sense to me that if you feed these exhaust gasses from the front edge outward,,,as we know they do, then as they bend backwards they flood the edge and form a skirt of charged moving air,,,but hey what do I know? I know that even to them it's a "black art" and they aren't even totally sure what the effects of the things they're doing are. They can't do full scale rolling roadbed wind tunnel testing...they can't even get their measurements correct from the scale one..they're guessing and so are we.

Makes no sense restating the facts.

There is a lot of evidence in the real life shots.

They don't go under the floor and that's that. End of.

this is the last repost. And it shows clearly how the gurneys come in and how there is no reason for gas to under floor.
http://i1010.photobucket.com/albums/af2 ... haust2.jpg

The interaction with the underside of the leading edge is as far as it goes.

It's not physically possible for it to curve under. So let them keep hollering,
It wont change the facts.

We need to move on to the actual downforce numbers now as the diffuser thing is debunked, and the eggs have found their faces.