Under floor flow & diffusers

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turbof1
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Re: Under floor flow & diffusers

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For the record, chuckdanny: Variante praises the effort you've done so far. Probably not in enough words to make it apparent, but he does :P.

He has a point when he says the sidepods don't create that kind of vortices. I encourage you though to keep up the work and slowly move towards a full and accurate F1 model. I encourage that because frankly you got me curious!
#AeroFrodo

chuckdanny
chuckdanny
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Re: Under floor flow & diffusers

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@turboF1: ok! you know him better than me.

I can't get rid of those vortices sorry, maybe in the billionth iteration... i can't wait...
You should consider that everywhere i appeared to find a vortex, f1 engineer are putting some strange stuff with bizarre name, like this slot in front of the rear tires or winglet on top of sidepod and near the mirror... Horns in outer front floor corner etc...
But i know, it's one of there job to make some dissapear and reinforce others. Another great hint from flash gordon coming from outer space, vortices that rotate in the same direction tends to attract each others and merge (and reinforce? don't remember) while conter-rotating ones repel so are the rules to assemble those vortex pieces... mindstorm lego...

Matter:
Image
Antimatter
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astracrazy
astracrazy
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Re: Under floor flow & diffusers

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Thanks chuckdanny for this thread. One of my favourites at the moment.

chuckdanny
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Re: Under floor flow & diffusers

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So i'm not the only one to be interested in those little tornadoes ? :wink:

I think i miscalculated my y250 like vortex, it goes straight into the leading edge of the bargeboard... and die...

Image

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variante
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Re: Under floor flow & diffusers

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chuckdanny wrote:I think i miscalculated my y250 like vortex, it goes straight into the leading edge of the bargeboard... and die...
In reality the Y250 goes straight into the turning vanes (so a little more outward) and dies. Therefore its funcion must be fullfilled somewhere (and somehow) between the front wing and floor's leading edge.

About its function, i've found that vortex to be useful enhancing the extraction from the front wing itself. But obviously that's not its only purpose, otherwise F1 aerodynamicists would't have bothered making that vortex stable through all its lenght...

BTW, chuckdanny, in your case you could try to merge the Y250 with the bardgeboard upper vortex.
...and...how about a front wing? :D

Just_a_fan
Just_a_fan
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Re: Under floor flow & diffusers

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Without a front wing and the flow coming off it, this otherwise excellent thread doesn't tell us anything about the cars we enjoy. Keep up the good work! =D>
If you are more fortunate than others, build a larger table not a taller fence.

astracrazy
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Re: Under floor flow & diffusers

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so what is causing his y250 to stay inboard? Lack of front wing creating low pressure behind it or something?

wesley123
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Re: Under floor flow & diffusers

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chuckdanny wrote:So i'm not the only one to be interested in those little tornadoes ? :wink:

I think i miscalculated my y250 like vortex, it goes straight into the leading edge of the bargeboard... and die...

http://oi61.tinypic.com/kf5wcn.jpg
Wouldn't that be the point? Utilize the vortex to allow a clean path of air towards the bargeboard/floor?
"Bite my shiny metal ass" - Bender

chuckdanny
chuckdanny
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Re: Under floor flow & diffusers

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Yes, the vortex gearing create a kind of shielding flow condition. I maybe wrong, i'm not jesus christ (do you believe me?) but of course that's what we hear sometimes.
I can illustrate now :

http://oi59.tinypic.com/2v36g74.jpg

I have great difficulties to make the flow nicely sweep the back facing surface of the coke bottle shape. I often get recirculating swimming pool there. And i think at top speed it should be worse.( I know you can improve with the sidepod shape and we all know there are great variations from the teams in this area.)
And then all of a sudden as if the shielding offered a constrain highly needed i get this :

http://oi60.tinypic.com/2wd105i.jpg

Call this reenergize the swimming pool to stop the dirt or spread the sù$^$!

That's not perfect but far better, but again i make an easy correlation because that's what i was waiting for to be honest.
In general i still think that my 2d models were kind of relevant. You got 3 accelerating area which should work together at least at certain speed to maximise downforce or effiency or both. But because it's 3d now, the connection between subsystem is harder to get, air as more freedom, DOF as they say in multibody dynamic so it tends to relax to much and wander around.

Again but it's not from him i think this time, at least i learn from the lecture of flash gordon mccabe (he comes from area 51 => le pastaga) that vortices are the muscle and bones of aerodynamics, more fondamentals that pressure field and velocity field. It comes from the biot savard law (not joe it's a french :mrgreen: ) but it doesn't mean that vortices create pressure more than the other way around rather that they are (vortices) bones that is solid structure on which you can withstand adversity :) and muscles in that you can steer the whole body flow thanks to them. To sum up command and control.
But of course you knew all that... and that there are absolutly no vortices at the back :P

chuckdanny
chuckdanny
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Re: Under floor flow & diffusers

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And noOW !! ladies and gentlemen, you will see what nobody is able to see with human eyes, exclusively for F1technical and for the 1st time in the world !! A massive phenomenon that has more to do with hurricanes than vortices, a Y250 vortex merging with 2 little bargeboard natives vortices coming from the top leading edge and the bottom trailing edge of a diagonally cut triangular bargeboard. You won't believe your eyes, the merge create a real wall, it could protect a tank from manpad and and furthermore it has sufficient energy to survive this exhausting task and doing the job of sealing the sidepod undercut all along!

That's a real tour de force!
http://oi58.tinypic.com/4q0k7l.jpg

Another point of view
http://oi58.tinypic.com/jfgmqq.jpg

front tire dirty air has no chance ! you shall not pass !
http://oi60.tinypic.com/2gxfmuu.jpg

PhillipM
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Location: Over the road from Boothy...

Re: Under floor flow & diffusers

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That looks very similar to what we saw on the RB a few years ago.

chuckdanny
chuckdanny
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Re: Under floor flow & diffusers

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Technical art :

Image

Image

chuckdanny
chuckdanny
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Re: Under floor flow & diffusers

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Two things are astonishing, of course the low res mesh is a big caveat to any interpretation.

1st, the vortex path is pretty much the same as seen on rb end ferrari and that without front and rear wings. So the claim that front wing would completly change the flow structure seems false. The mandatory almost flat center section of fw of course is the main reason, i expect the front wing to control the vortices from the back of the tire and limiting the downwash of tires hence there lift, postponing the encounter between tire wake and floor so that it goes over it right into the sidepod shield preventing it from going under the floor which is the case actually. plus additionnal sidewash from the endplate.

2nd, i expected a change with speed from the vortex path and i can't see any. The strenght of the vortex of course change i tested from 40m/s (144km/h) to 84(300km/h).

ArgyrisB
ArgyrisB
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Re: Under floor flow & diffusers

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regarding the diffuser discussion.
The primary purpose of the diffuser is to expand air resulting to drop of velocity and therefore increase in pressure. So it creates a pressure potential which will accelerate the flow underneath the car. However in the previous images we have seen that in the area of the diffuser the pressure is lower than the pressure underneath the car not higher as one would except.
What's the explanation, cause i've been confused :?

chuckdanny
chuckdanny
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Re: Under floor flow & diffusers

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ArgyrisB wrote:regarding the diffuser discussion.
The primary purpose of the diffuser is to expand air resulting to drop of velocity and therefore increase in pressure. So it creates a pressure potential which will accelerate the flow underneath the car. However in the previous images we have seen that in the area of the diffuser the pressure is lower than the pressure underneath the car not higher as one would except.
What's the explanation, cause i've been confused :?
You lost me on this one!
The primary purpose of a diffuser is to drop velocity ? I don't think so, it's the opposite it create an acceleration at the throat hence a pressure drop there or the other way around, what comes next is a by product. Next you say it creates a pressure potential that will accelerate the flow, from rear to front then ? :lol:

My explanation, which i recon can be naiv, the back face of a diffuser liberate the thermomentum of the air in a specific direction which then has a local acceleration and fill the gap (if you no longer go for a gap, your not a racing driver, this mentality is in the air... also), there is a kind of darwinian segregation process that appends which select the well oriented molecules if the design is well suited.

That's a plate in ground effect without rake and with diffuser
http://oi57.tinypic.com/155nnl2.jpg