Formula 1 Aerodynamics - article series and general discussion

Here are our CFD links and discussions about aerodynamics, suspension, driver safety and tyres. Please stick to F1 on this forum.
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Zynerji
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Re: Formula 1 Aerodynamics - article series and general discussion

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I think we have seen nature lead designs for a bit now, from humpback whale fins to bird feathers.

I agree that a lift-inducing design in that area could be traded for a net downforce gain.

I disagree that F1 floors could fly upside down. (No ground effect scalar)

If the falcon shape accelerates air up and over the top surface to generate lift, it doesn't seem impossible that the concept could be harnessed to increase air velocity over the top of the diffuser to generate downforce. (ground effect scaled)

It's all brilliant, no matter the source.

Just_a_fan
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Re: Formula 1 Aerodynamics - article series and general discussion

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godlameroso wrote:
Thu Apr 01, 2021 11:37 pm
Just_a_fan wrote:
Thu Apr 01, 2021 10:20 pm
Resembling in appearance does not mean they are similar in action.
In nature, form tends to be strongly correlated with function. From chemistry to physics. Unless the birds are using a different type of air than F1 cars, then they're subject to the same physical laws.

What's good for the goose, is good for the...F1 gander.
If you can show a bird using its alula to control tyre wake and inflow around a ground effect floor, you might have a point in comparing birds and cars.

Yes, both work with air, but they aren't doing the same things for the same reasons.

In a stooping falcon, the alula isn't acting as a vg trying to turn air away from a sensitive zone, it's acting as a control surface to steer the bird in combination with the tail.
Turbo says "Dumpster sounds so much more classy. It's the diamond of the cesspools." oh, and "The Dutch fans are drunk. Maybe"

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godlameroso
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Re: Formula 1 Aerodynamics - article series and general discussion

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Just_a_fan wrote:
Fri Apr 02, 2021 1:18 am
godlameroso wrote:
Thu Apr 01, 2021 11:37 pm
Just_a_fan wrote:
Thu Apr 01, 2021 10:20 pm
Resembling in appearance does not mean they are similar in action.
In nature, form tends to be strongly correlated with function. From chemistry to physics. Unless the birds are using a different type of air than F1 cars, then they're subject to the same physical laws.

What's good for the goose, is good for the...F1 gander.
If you can show a bird using its alula to control tyre wake and inflow around a ground effect floor, you might have a point in comparing birds and cars.

Yes, both work with air, but they aren't doing the same things for the same reasons.

In a stooping falcon, the alula isn't acting as a vg trying to turn air away from a sensitive zone, it's acting as a control surface to steer the bird in combination with the tail.
It does act like a VG, that's how airflow stays attached in its "cupped" configuration.

Another interesting bit is how the inner wing acts like a cape for the tail, very obvious when they spread their wings. Same contour, same function, providing clean air to their diffuser/tail to keep it from stalling.
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hollus
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Re: Formula 1 Aerodynamics - article series and general discussion

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Just my two cents, I don’t necessarily know what i am talking about:
There are only so many possible shapes, and if one compares each of them to enough animals, and then to enough parts of enough animals, some are bound to look similar.
Humans are really good at finding patterns and similarities, too good, we are biased towards false positives (which are mostly harmless unless being eaten due to a false negative); it does not mean that they are significant or important.

Also: F1 floor shapes are mostly bound by the rules, only after that by the laws of physics.
I would like to see a paleontologist.

Just_a_fan
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Re: Formula 1 Aerodynamics - article series and general discussion

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godlameroso wrote:
Fri Apr 02, 2021 12:33 pm
Just_a_fan wrote:
Fri Apr 02, 2021 1:18 am
godlameroso wrote:
Thu Apr 01, 2021 11:37 pm


In nature, form tends to be strongly correlated with function. From chemistry to physics. Unless the birds are using a different type of air than F1 cars, then they're subject to the same physical laws.

What's good for the goose, is good for the...F1 gander.
If you can show a bird using its alula to control tyre wake and inflow around a ground effect floor, you might have a point in comparing birds and cars.

Yes, both work with air, but they aren't doing the same things for the same reasons.

In a stooping falcon, the alula isn't acting as a vg trying to turn air away from a sensitive zone, it's acting as a control surface to steer the bird in combination with the tail.
It does act like a VG, that's how airflow stays attached in its "cupped" configuration.

Another interesting bit is how the inner wing acts like a cape for the tail, very obvious when they spread their wings. Same contour, same function, providing clean air to their diffuser/tail to keep it from stalling.
Oh please.
Turbo says "Dumpster sounds so much more classy. It's the diamond of the cesspools." oh, and "The Dutch fans are drunk. Maybe"

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Zynerji
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Re: Formula 1 Aerodynamics - article series and general discussion

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Just_a_fan wrote:
Fri Apr 02, 2021 9:59 pm
godlameroso wrote:
Fri Apr 02, 2021 12:33 pm
Just_a_fan wrote:
Fri Apr 02, 2021 1:18 am

If you can show a bird using its alula to control tyre wake and inflow around a ground effect floor, you might have a point in comparing birds and cars.

Yes, both work with air, but they aren't doing the same things for the same reasons.

In a stooping falcon, the alula isn't acting as a vg trying to turn air away from a sensitive zone, it's acting as a control surface to steer the bird in combination with the tail.
It does act like a VG, that's how airflow stays attached in its "cupped" configuration.

Another interesting bit is how the inner wing acts like a cape for the tail, very obvious when they spread their wings. Same contour, same function, providing clean air to their diffuser/tail to keep it from stalling.
Oh please.
Why such strong pushback? 🤔

This seems to be more about Cause:Effect than Intent:Outcome, and it may correlate correctly in that way.

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godlameroso
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Re: Formula 1 Aerodynamics - article series and general discussion

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Looks like teams are working to guide airflow towards the low pressure turbulent area of the tire, that's what I would do if I wanted to lessen the turbulence of the tire on the inboard side.

The only real way to send airflow down to the low pressure tire squirt region without slots is to make the floor thicker, then thinner at the edge to create a downward slope.
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hecti
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Re: Formula 1 Aerodynamics - article series and general discussion

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This seems like far fetched but don't we have to look at not only the air underneath and above the floor, but the air coming over the sidepod as well? There are 3-4 distinct flows that all converge in roughly the same area, if the more "Z" shaped cut out is really acting like an Alula (which seems very possible, as falcons can reach the same speeds F1 cars can) then maybe we can draw some conclusions as to what is going on. When looked at individually we don't see the clear picture. If we assume that the y250 vortex, strengthened by the barge boards and then merged with the underbody flows that exit from the sides of the floor after the barge boards all converge, then it leaves a gap that needs to be filled, mostly by the air coming over the side pods which most have a slope element towards the cutout and maybe flow over the flow that comes around the under cut of the sidepod. this flow interacts with the cutout and the small floor edge VGs to create a vortex that may seem like a leaky edge but actually seals the diffuser from the inward tire squirt further back. The harder the air floor is worked underneath (ie: high rake) at the beginning of the floor the more effective the cutout vortex is.

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Re: Formula 1 Aerodynamics - article series and general discussion

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hecti wrote:
Mon Apr 12, 2021 4:20 pm
This seems like far fetched but don't we have to look at not only the air underneath and above the floor, but the air coming over the sidepod as well? There are 3-4 distinct flows that all converge in roughly the same area, if the more "Z" shaped cut out is really acting like an Alula (which seems very possible, as falcons can reach the same speeds F1 cars can) then maybe we can draw some conclusions as to what is going on. When looked at individually we don't see the clear picture. If we assume that the y250 vortex, strengthened by the barge boards and then merged with the underbody flows that exit from the sides of the floor after the barge boards all converge, then it leaves a gap that needs to be filled, mostly by the air coming over the side pods which most have a slope element towards the cutout and maybe flow over the flow that comes around the under cut of the sidepod. this flow interacts with the cutout and the small floor edge VGs to create a vortex that may seem like a leaky edge but actually seals the diffuser from the inward tire squirt further back. The harder the air floor is worked underneath (ie: high rake) at the beginning of the floor the more effective the cutout vortex is.
When thinking of air, you have to consider the air around the object. Some air is attached to the car due to viscous forces, and that air gets dragged along with the car, but the air around the object is not. The dragged air along the vehicle skin and the boundary where the dragged air stops interacting with the surrounding air is called the boundary layer.

The air being dragged by the car IE the boundary layer is moving faster than the air above and around it, this faster air lowers its pressure.

Imagine a Jenga tower, and the blocks are the air, and the floor is the skin on the car, if you skillfully pull the bottom layer of blocks, all the blocks above will collapse their mass on the space below. The air that surrounds the boundary layer does the same thing because air is at 14.7psi at sea level, so when the car drags air behind it, the static high pressure air above it is at atmospheric pressure and collapses on the low pressure caused by the faster moving air below the boundary layer.

When you create a high pressure circulation, entrained low pressure like a vortex, will go around this high pressure zone. You can see this in the path of hurricanes across the ocean, high pressure troughs push the storm, and low pressure systems pull the storm. If we translate this to F1, we see the diffuser, being a low pressure system pulls the low pressure tire squirt into itself. The low pressure side being the rear of the tire, and the high pressure side being the front of the tire, the squirt itself is the high pressure in the front rushing to fill the low pressure in the back of the tire. That turbulent low pressure vortex gets steered by the low pressure created by the diffuser.

Now with lower rake, that tire squirt is more powerful, because the diffuser is closer to the ground, there are no slots to lower the pressure on the face of the tire, which reduces the pressure difference and weakens the tire squirt.

The challenge of the teams is to use the new floor to either increase the pressure at the rear of the tire, or lower the pressure at the front of the tire, or both.
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godlameroso
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Re: Formula 1 Aerodynamics - article series and general discussion

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This leads to another interesting concept. The shape that your eyes see is not the shape the air sees. The boundary layer changes the actual shape of the car, because the boundary layer is time dependent and is both turbulent and laminar. The high pressure and hot surfaces are in practice bigger for airflow than they appear because of the "thicker" boundary layers due to increased viscosity and surface drag. Likewise, low pressure surfaces where the airflow is very high speed and very close to the body work is actually closer to its physical dimensions in an aero disturbance sense.
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hecti
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Re: Formula 1 Aerodynamics - article series and general discussion

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Here are two images from Perez's blow from Bahrain last year, if you look even though you would think that the floor cut outs would make it seem that they should be helping move the air to the outside of the tire, in reality, the majority of the steam gets pulled into a vortex towards the inside of the tire, protecting the diffuser from tire squirt.

Image
Image

All I am saying is that the higher rake cars can use their rake advantage to create a stronger underside floor edge vortex because of the greater suction effect the high rake provides. The cut out in the end affects both sides (high and low rake) but high rake cars seem to loose less than high rake.

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godlameroso
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Re: Formula 1 Aerodynamics - article series and general discussion

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hecti wrote:
Mon Apr 12, 2021 7:54 pm
Here are two images from Perez's blow from Bahrain last year, if you look even though you would think that the floor cut outs would make it seem that they should be helping move the air to the outside of the tire, in reality, the majority of the steam gets pulled into a vortex towards the inside of the tire, protecting the diffuser from tire squirt.

https://i.redd.it/y437bb28nc261.jpg
https://www.formula1.com/content/dam/fo ... 9BT6gBR9fh

All I am saying is that the higher rake cars can use their rake advantage to create a stronger underside floor edge vortex because of the greater suction effect the high rake provides. The cut out in the end affects both sides (high and low rake) but high rake cars seem to loose less than high rake.
I like those pictures, I posted them last year a few times to illustrate the same thing. Forum regular Platinum Zealot has the correct interpretation, the slots do make little vortecies, and they merge with the tire squirt. Remember that vortecies get pulled by low pressure systems and pushed by high pressure ones. Therefore, they're pushed by the tire face, and pulled by the tire wake. Furthermore the vortcies they shed merge with the main diffuser because they have the same angular momentum.

So I think this is a productive discussion and appreciate your feedback, as it has helped me understand. The vortex from the slots stalls the tire squirt because it reduces the pressure difference between the front and rear of the tire. The air on the walls of the vortex are high pressure because the centrifugal force of the vortex creates its own boundary layer. That high pressure boundary layer fills in the low pressure behind the tire.

You have part of the puzzle as do I, our fingers are both pointing to the moon but my finger is uglier than yours.
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Just_a_fan
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Re: Formula 1 Aerodynamics - article series and general discussion

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godlameroso wrote:
Mon Apr 12, 2021 9:08 pm
The air on the walls of the vortex are high pressure because the centrifugal force of the vortex creates its own boundary layer. That high pressure boundary layer fills in the low pressure behind the tire.

A vortex is a core of low pressure which tends to the local pressure as one goes further from the core. There is low pressure and there is "freestream pressure" and there is the gradient between the two. There is no high pressure wall around a vortex other than the relatively higher pressure in the freestream. There is a gradient boundary layer effect just as there is with a wing.
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godlameroso
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Re: Formula 1 Aerodynamics - article series and general discussion

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Just_a_fan wrote:
Mon Apr 12, 2021 10:42 pm
godlameroso wrote:
Mon Apr 12, 2021 9:08 pm
The air on the walls of the vortex are high pressure because the centrifugal force of the vortex creates its own boundary layer. That high pressure boundary layer fills in the low pressure behind the tire.

A vortex is a core of low pressure which tends to the local pressure as one goes further from the core. There is low pressure and there is "freestream pressure" and there is the gradient between the two. There is no high pressure wall around a vortex other than the relatively higher pressure in the freestream. There is a gradient boundary layer effect just as there is with a wing.
Yes there is. The core of the vortex is low pressure, the spinning low pressure has centrifugal force which pushes air outwards creating the wall of the vortex and gives the core its low pressure.

Image

Outside of the core the pressure is higher or the vortex would lose integrity, you can't have a vortex without high pressure air rushing to fill low pressure. Wing tip vortecies exist precisely because high pressure air is trying to fill the low pressure on the other side of the wing.
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Tommy Cookers
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Re: Formula 1 Aerodynamics - article series and general discussion

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godlameroso wrote:
Tue Apr 13, 2021 1:33 am
... Wing tip vortecies .....
vortices

vortex & vortices

(e.g. matrix & matrices or index & indices)
Last edited by Tommy Cookers on Tue Apr 13, 2021 4:47 pm, edited 1 time in total.