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.
Dipesh1995
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Re: Formula 1 Aerodynamics - article series and general discussion

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A couple of good free publications which will be of interest to both of you; the first one is particularly good.

https://www.researchgate.net/profile/St ... ion_detail

https://www.researchgate.net/profile/Sa ... ion_detail

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

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Hmm it seems there's a lot of interesting disturbances between small and large vortex interaction, and that they won't necessarily merge. However in F1 terms I think they do merge, and at lower speeds the don't because the cores are much smaller. I think this also explains why some teams are more sensitive to tail or cross winds. Because smaller weaker vortecies at lower speeds get broken up by tail winds, or strengthened by head winds or certain cross winds. At higher speeds the vortecies all merge into the main diffuser wake, so it no longer makes a difference.

The rear of the car forms all sorts of vortecies that can affect how and when they merge with the main one.

It's of special interest that, like a screw driven compressor, two counter rotating vortecies can in fact create a displacement of air.

If you look at the counter rotating vortecies coming off the back of the car, it become apparent. This is why ground effect or no ground effect, the following car will always lose massive performance. They're driving into a low pressure region due to the counter rotating vortecies displacing air upwards. A secondary and lesser power rooster tail if you will.


Here's a hypothesis, which I can see playing out this year because of the new rules.

A chasing driver can, to an extent drive around the bad aero of the car in in front, or use it as a slipstream. The wider the car, the harder it makes it for the following driver to drive around the bad aero of the lead car. However if the wide car is throwing out wide vortecies to encourage diffuser flow, this vortex will actually help the chasing car. As counter intuitive as it seems, powerful bargeboards actually promote closer racing. It will let the following car, drive along the vortex being shed by the bargeboard, allowing one to maintain more downforce than otherwise would be possible directly behind.

I'm sure anyone with a brain is thinking, wouldn't just driving behind the leading car increase downforce if that were true, two huge counter rotating vortecies to pick from. Except no, the wake behind the car is pure low pressure, so driving directly behind the car will lower downforce because of the nature of the wake. The two counter rotating vortecies are pumping air upwards creating a pressure reduction.

The vortecies being shed by the bargeboards are not passing through the diffuser, they are just a wall of organized air with a kinetic component, and no bodywork to trip them up. Just distance, thus a chasing driver can use them to his advantage.
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hollus
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Re: Formula 1 Aerodynamics - article series and general discussion

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Except no, the wake behind the car is pure low pressure, so driving directly behind the car will lower downforce because of the nature of the wake. The two counter rotating vortecies are pumping air upwards creating a pressure reduction.
I don't think that is correct. The rear of the car and those counter-rotating vortices indeed throw air upwards at the car's centerline. But that doesn't mean that you get a partial vacuum ("low pressure") behind the leading car at ground level. It just means that new air has to come in from the sides to fill that space. And that air will, partially because it has to fill the otherwise vacant space, be moving forwards (and a bit sideways).
So one could say that there is low pressure behind the leading car, but only in the "dynamic" meaning of low pressure. Static pressure is pretty close to 1 atmosphere everywhere.
In a car's wake, at ground level, you do encounter air with the same density, there is no vacuum, but the speed of that air relative to your car is slower, hence less downforce.

But I might be getting it wrong, of course; either the physics or the terminology.
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Re: Formula 1 Aerodynamics - article series and general discussion

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hollus wrote:
Fri Feb 19, 2021 7:53 pm
Except no, the wake behind the car is pure low pressure, so driving directly behind the car will lower downforce because of the nature of the wake. The two counter rotating vortecies are pumping air upwards creating a pressure reduction.
I don't think that is correct. The rear of the car and those counter-rotating vortices indeed throw air upwards at the car's centerline. But that doesn't mean that you get a partial vacuum ("low pressure") behind the leading car at ground level. It just means that new air has to come in from the sides to fill that space. And that air will, partially because it has to fill the otherwise vacant space, be moving forwards (and a bit sideways).
So one could say that there is low pressure behind the leading car, but only in the "dynamic" meaning of low pressure. Static pressure is pretty close to 1 atmosphere everywhere.
In a car's wake, at ground level, you do encounter air with the same density, there is no vacuum, but the speed of that air relative to your car is slower, hence less downforce.

But I might be getting it wrong, of course; either the physics or the terminology.
I get what you're saying, as the car moves forward it gives the air some forward momentum as that air fills the partial vacuum the car leaves in its wake. It's the macro movement of the car and the air rushing to fill the low pressure created as the car moves across the road.
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Induction and entrainment, what part of the car does this, oh yeah the rear tires.
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Start at 2:08

I found this information fascinating, and adds to the conversation.
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Re: Formula 1 Aerodynamics - article series and general discussion

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Image
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hUirEYExbN
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Re: Formula 1 Aerodynamics - article series and general discussion

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godlameroso wrote:
Thu Apr 01, 2021 3:54 pm
https://files.catbox.moe/54wec0.png
That's a nice picture, but it doesn't mean anything on its own.

How does the alula of a falcon relate to that part of the floor? What's your thesis?

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Re: Formula 1 Aerodynamics - article series and general discussion

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hUirEYExbN wrote:
Thu Apr 01, 2021 4:33 pm
godlameroso wrote:
Thu Apr 01, 2021 3:54 pm
https://files.catbox.moe/54wec0.png
That's a nice picture, but it doesn't mean anything on its own.

How does the alula of a falcon relate to that part of the floor? What's your thesis?
The part on the car and the falcon alula are both creating a tip vortex that helps keep airflow attached to the wing/top side of the floor.

Both the bird and car have a similar profile from the alula to the tip of the wing, and the device on the car to the tapered section of the floor. My thesis is that the bird design can help guide the development of the car.

Of course the bird is trying to generate lift(the inverse of an F1 car), and the bird doesn't come with spinning tires, but the design principles are the same. The bird is trying to guide airflow in a similar manner to an F1 car only inverted.

If you notice, the alula curves inward, while the device on the F1 car curves outward, IE inverted.
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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:
Thu Apr 01, 2021 5:22 pm
hUirEYExbN wrote:
Thu Apr 01, 2021 4:33 pm
godlameroso wrote:
Thu Apr 01, 2021 3:54 pm
https://files.catbox.moe/54wec0.png
That's a nice picture, but it doesn't mean anything on its own.

How does the alula of a falcon relate to that part of the floor? What's your thesis?
The part on the car and the falcon alula are both creating a tip vortex that helps keep airflow attached to the wing/top side of the floor.

Both the bird and car have a similar profile from the alula to the tip of the wing, and the device on the car to the tapered section of the floor. My thesis is that the bird design can help guide the development of the car.

Of course the bird is trying to generate lift(the inverse of an F1 car), and the bird doesn't come with spinning tires, but the design principles are the same. The bird is trying to guide airflow in a similar manner to an F1 car only inverted.

If you notice, the alula curves inward, while the device on the F1 car curves outward, IE inverted.
The stooping falcon is a lifting body and the alula is a roll control device. There is no correlation between what a stooping falcon is doing and what an F1 car is doing with the air flow along the edge of the floor.

The alula curves the way it does because it's normally held against the surface of the wing and the feathers are shaped accordingly.

The F1 floor edge VGs are designed to roll up a vortex that spins in a specific direction in order to interact with other similar vortices generated up stream.

Where the alula does mimic human designs (or rather vice versa) is in high angles of attack. Then the alula performs a similar role to the leading edge slats on a human-built aircraft wing.
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Re: Formula 1 Aerodynamics - article series and general discussion

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Just_a_fan wrote:
Thu Apr 01, 2021 6:10 pm
godlameroso wrote:
Thu Apr 01, 2021 5:22 pm
hUirEYExbN wrote:
Thu Apr 01, 2021 4:33 pm


That's a nice picture, but it doesn't mean anything on its own.

How does the alula of a falcon relate to that part of the floor? What's your thesis?
The part on the car and the falcon alula are both creating a tip vortex that helps keep airflow attached to the wing/top side of the floor.

Both the bird and car have a similar profile from the alula to the tip of the wing, and the device on the car to the tapered section of the floor. My thesis is that the bird design can help guide the development of the car.

Of course the bird is trying to generate lift(the inverse of an F1 car), and the bird doesn't come with spinning tires, but the design principles are the same. The bird is trying to guide airflow in a similar manner to an F1 car only inverted.

If you notice, the alula curves inward, while the device on the F1 car curves outward, IE inverted.
The stooping falcon is a lifting body and the alula is a roll control device. There is no correlation between what a stooping falcon is doing and what an F1 car is doing with the air flow along the edge of the floor.

The alula curves the way it does because it's normally held against the surface of the wing and the feathers are shaped accordingly.

The F1 floor edge VGs are designed to roll up a vortex that spins in a specific direction in order to interact with other similar vortices generated up stream.

Where the alula does mimic human designs (or rather vice versa) is in high angles of attack. Then the alula performs a similar role to the leading edge slats on a human-built aircraft wing.
Wouldn't this be beneficial if you're interested in increasing the pressure of the upper side of the floor near the rear tire?

Place one on the floor edge before it tapers allowing you to run higher angle of attack on the geometry of the floor near the rear tires.

Place them ahead of the bargeboards so that airflow from the Y250 stays attached to bargeboards and deflectors despite the high angle of attack.

Yes, I'm aware they already do this.

Where I'm interested is in the way the wing tapers down, like the floors do. Although if we have to invert the bird for it to work in F1...

Image

There's absolutely no similarity in design?

If you turn the floor upside down, it'll generate lift like the bird, if you turn the bird upside down, it'll create downforce like the floor.
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hUirEYExbN
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Re: Formula 1 Aerodynamics - article series and general discussion

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godlameroso wrote:
Thu Apr 01, 2021 5:22 pm
hUirEYExbN wrote:
Thu Apr 01, 2021 4:33 pm
godlameroso wrote:
Thu Apr 01, 2021 3:54 pm
https://files.catbox.moe/54wec0.png
That's a nice picture, but it doesn't mean anything on its own.

How does the alula of a falcon relate to that part of the floor? What's your thesis?
The part on the car and the falcon alula are both creating a tip vortex that helps keep airflow attached to the wing/top side of the floor.

Both the bird and car have a similar profile from the alula to the tip of the wing, and the device on the car to the tapered section of the floor. My thesis is that the bird design can help guide the development of the car.

Of course the bird is trying to generate lift(the inverse of an F1 car), and the bird doesn't come with spinning tires, but the design principles are the same. The bird is trying to guide airflow in a similar manner to an F1 car only inverted.

If you notice, the alula curves inward, while the device on the F1 car curves outward, IE inverted.
OK, I understand the connection you are making.

My understanding is that falcons use their alulae to fine control force and moment balance (and consequently flight direction) when in their freefalling teardrop stage. The car uses their floor doohickies to keep flow attached over the upper surface of the floor?

If I'm right in my assumptions there, then I'm not sure I see any connection other than purely cosmetic.

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Re: Formula 1 Aerodynamics - article series and general discussion

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Then why put them on the bargeboards and edge of the floor? You can see on the picture above on the floor of the McLaren that the little flicks right before the floor tapers resembles the bird.
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Just_a_fan
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Re: Formula 1 Aerodynamics - article series and general discussion

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Resembling in appearance does not mean they are similar in action.
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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:
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.
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