2022 Aerodynamic Regulations Thread

[Slo Poke]

A brief on the theory and application of aerodynamic appendages

Thank you for taking the time to do this. I know fairly little about aero but rather enjoy reading the technical bits. It becomes a bit difficult to know which way is up when you have users throwing around factoids, so I (and I'm sure many other silent readers) appreciate when the more reputable members step in.

I take it you mean factoids offered by enthusiastic forum members rather than those oft dished out willy-nilly by secretively misleading f1 teams!

[Chuckjr]

Since these cars use the Bernoulli effect for most of their downforce starting this year, I’d like to better understand the forgiveness or lack thereof, of this aero anomaly.

So my main question is, is the break point for the “suck effect” of this system sudden, or is it forgiving?

For instance, if the car lifts off the ground from a curb bump and jumps, say, an inch or so past the main suck point (I’m assuming that’s the pinch point before the opening to the end of the car), will the car suddenly lose a majority of its downforce and tend to lift more easily? Or, is Bernoulli’s amazing suck zone a forgiving one, and the car can go 1”, heck even 2” past the main downforce driving area and still maintain most of the sucking effect?

Bonus round:
How large is the area that generates the majority of the downforce under the car, and what percentage of downforce does that area generate overall? Or is the downforce evenly spread over the whole of the bottom of the car, and the pinch point is simply the beginning of the suck effect.

If these details have already been elucidated, please point me to the page. Thank you.

Thank you for any and all answers. This place is amazing when it comes to explaining the engineering of this fantastic sport, and I appreciate the insight offered in the engineering forums here. Thank you insightful contributors — your efforts are appreciated.

[Stu]

Since these cars use the Bernoulli effect for most of their downforce starting this year, I’d like to better understand the forgiveness or lack thereof, of this aero anomaly.

So my main question is, is the break point for the “suck effect” of this system sudden, or is it forgiving?

For instance, if the car lifts off the ground from a curb bump and jumps, say, an inch or so past the main suck point (I’m assuming that’s the pinch point before the opening to the end of the car), will the car suddenly lose a majority of its downforce and tend to lift more easily? Or, is Bernoulli’s amazing suck zone a forgiving one, and the car can go 1”, heck even 2” past the main downforce driving area and still maintain most of the sucking effect?

Bonus round:
How large is the area that generates the majority of the downforce under the car, and what percentage of downforce does that area generate overall? Or is the downforce evenly spread over the whole of the bottom of the car, and the pinch point is simply the beginning of the suck effect.

If these details have already been elucidated, please point me to the page. Thank you.

Thank you for any and all answers. This place is amazing when it comes to explaining the engineering of this fantastic sport, and I appreciate the insight offered in the engineering forums here. Thank you insightful contributors — your efforts are appreciated.

I’ll try to answer a couple of these…

Sensitivity to ride height
At this point we do not know. The teams think they know, but need to confirm with actual testing. Historically, if the highest downforce is ‘peaky’ then the car will be very sensitive to ride height; but a car with broad peak (but less maximum downforce) will be less sensitive to ride height. Obviously a high broad peak that is not too sensitive would be the best compromise (but probably like trying to hunt down a unicorn…).

Because of how the tunnels are shaped (and assuming that they follow Bernoulli’s theory, the entrance of the tunnel should be speeding up the airflow, such that the peak speed (and lowest pressure) occurs at the leading edge of the flat section of floor, the longer this low pressure area can be maintained the better, the outlet (tunnel exit) should be designed to slow the airflow back to the same air speed (and pressure) that is present at the rear of the car. The tunnels should be designed to do this efficiently without stagnation points. This is probably why we are seeing ‘stepped’ tunnels in the launch cars.

This will tend to work alongside the ride height sensitivity as if the floor becomes ‘choked’ and cannot allow the airflow through the high-speed flat section (throat), all downforce generated by the floor disappears and an effect known as porpoising occurs. This is a bad thing.

Until they know the exact behaviour of the cars expect the drivers to be very respectful of the kerbs at the corner apex.

Hope that helps.
And that it isn’t a load of old bollocks….

[djos]

The Lola Champ Cars had a partially enclosed tunnel section that I assume was there to reduce the cars sensitivity to riding curbs etc.

[jjn9128]

Another case of confused terminology. Car's will make "better" use of the VENTURI effect this year. The Bernoulli principal is that change in dynamic pressure results in an inverse change in static pressure.

As for ride height sensitivity, there is in the rules a minimum throat area, which basically all teams will run to. This should keep the worst of the stall behaviour away. Meaning the venturi throat never gets so low that the flow will choke. CFD and wind tunnel methods are also far more advanced than in 1982 so the cars are tested over a wide array of roll/yaw/pitch/ride height/steer angle/cornering (in CFD) to test the car in more than 1 idealised position. The optimal being to program in a benign characteristic which changing ride height. Even maybe trying to stall out the floor above a certain speed - with car taken that the hysteresis loop is small when trying to reconnect the flow.

Ground effect and the Venturi in particular are incredibly sensitive to even small ground clearance changes, so dropping over the back of a kerb will reduce the peak load momentarily - but this is no different to the past generation of cars, which optimized the floor for downforce. This is why I wrote "better" above - as the floors in the past generation still used Venturis but the 2022 spec should be better as the suction peak is around the middle of the car not right at the rear.

[Blackout]

This is why I wrote "better" above - as the floors in the past generation still used Venturis but the 2022 spec should be better as the suction peak is around the middle of the car not right at the rear.

This.

[PlatinumZealot]

Yup. When the cars bottom out there will still be a passage for decent air flow, and the if the opposite happens where one side of the car is lifted the air flow is design to be more stable with all these modern design tools. Shouldn't have porpoising or sudden lift offs with these new cars.

[theVortexCreatorY250]

I can weigh in on this since I've been involved with design of both openwheeled race cars and ground-effect vehicles.
They are completely different - the ground effect vehicle almost stagnates the airflow under the main wing and it's anhedral is favourable for both pontoon design as well as sealing.
Race cars are trying to do the opposite by expanding airflow out where the edge wing is, they just drop it down to maximise localised loading.

[mclaren111]

Craig Scarborough:

Brake duct bodywork will change a lot in #F12022. New rules prescribe and control what can be done around brakes and wheels.

[Red Rock Mutley]

Please excuse the naive areo question. I'm looking at the parts of the 2022 cars that teams have been coy about revealing the details. The sidepod cooling inlet features are one thing (Hass and Aston Martin). And I'm wondering if the 2022 trend to shape the sidepods as rudimentary replacements for bargeboards can be taken to the extreme by removing the cooling inlets entirely and obtaining air from elsewhere. The McLaren especially has piqued my interest. Is it practical to move the cooling intakes down to the tea-tray area - essentially under the car, between the two venturi tunnels?

[Just_a_fan]

Is it practical to move the cooling intakes down to the tea-tray area - essentially under the car, between the two venturi tunnels?

The driver's backside would be in the way. You wouldn't want to take inlets around the driver because that would mean taking space out of the underfloor inlet.

[djos]

Even if it was practical from a packaging point of view, at any hot race, it’s likely the cooling capability would be severely compromised by the radiant heat from 50c+ asphalt.

[Slo Poke]

I see no tunnels! I see only open to atmosphere ruts and grooves, so good luck maintaining entrainment in those! As for the so-called inlets at the front, all those will do is create a bow, or pressure wave, which to an extent, will ram feed air to the underfloor saturating any sort of ground effect into submission. One more thing! Diffusers, whether single or double kick or even triple kick, pull air from any direction whatsoever, so by the time any kind of this so-called ground effect principle becomes established the car is as likely as not going to be slowing for a corner.
There is a chance however that these ridiculous cars will or could be as fast as last year’s but it will only be because of weight, power, gearing and the fact that Pirelli apparently have been asked to use less marmalade in the rubber.

[dans79]

This is the thing with engineering, it is not a book subject, because the key part is seeing how the maths, the physics play out and how different systems interact with each other.

Having actually run college level physics labs, this is very true. It was obvious to me when a concept "clicked" with students.

[Vyssion]

Alright, I've done some clean up here to remove misleading information and reset the thread to the main topic. To those who posted comments questioning the facts presented, or wanting further clarification, your posts have also been removed just to keep the thread flowing cohesively, and you can rest easy that you are all good.

To summarise the conversation topic, and explain correctly what's going on with lifting vs. downforce ground effects:

• It basically just has to do with what the ground does in each particular system

• For lifting ground effect, air can't get out the way fast enough because of the ground, so gets trapped increasing pressure a bit (i.e. "ram pressure"), but also cause the ground disrupts the wingtip vortices (circulation cancellation), you get lower induced drag

• For downforce, new air can't rush in fast enough to raise the pressure back because of the ground's location (venturi effect) and they too also cancel circulation, however, they have a higher induced drag because of lower peak pressures generated from that venturi effect

I want to say, however, that these sorts of technical discussions are indeed valuable for the forum, and should be encouraged.

The only reason that I have acted to remove these posts, is because I felt that unless the reader was to sit and read in detail through multiple pages of comments, they would come to the wrong understanding of the physics at play here. Also, requiring people to read all through the less accurate information, only to then have the past pages "cancelled out" by any corrective post I, or someone else, would make seems like a waste of time for everyone.

Should people wish to spit-ball ideas about aerodynamics and whatnot, you are absolutely welcome to do so, but when exploring these kinds of ideas, please do so in a less authoritative-sounding manner, and make a dedicated thread to explore them.