2022 Aerodynamic Regulations Thread

[godlameroso]

I'm not making anything up, physics are physics, all subsonic fluid will accelerate when it flows through a convergent duct. Please explain how F1 cars suddenly are not subject to fluid dynamics?

What you have written is not strictly correct. A pressure differential must occur for the velocity to increase. In the case of an ICE, The piston is creating a substantial vacuum/sucking and thus a pressure differential.

Velocity stacks in an ICE are a flow conditioner more than anything, it’s about minimizing losses where atmosphere or a larger volume of air, as it enters a duct. They are also not to be seen in isolation, and they are just a visible portion of the duct that starts at the valve seat and ends at the stack. This doesn’t even get to the wave parts of it.

Velocity stacks are used on turbo props like helicopters and other slow moving aircraft. They are used because they accelerate airflow with fewer losses. In HVAC systems, converging ducts are used to accelerate air flow. In Turbofans, the bypass region is a converging duct which accelerates the flow. Ducted fans with a bell mouth inlet are more efficient, period. The diffuser on the 2022 cars are also converging ducts, IE venturi tunnels, same as they use in carburetors. By your logic the venturi tunnels in F1 cars shouldn't work because the venturi principle only works on carburetors?

When a car moves through the air, the moving car causes air to accelerate through the body work. In the case of a car moving through the air, the car is moving faster than a sprinting cheetah at all times, and thus creates a pressure differential.

[Hoffman900]

What you have written is not strictly correct. A pressure differential must occur for the velocity to increase. In the case of an ICE, The piston is creating a substantial vacuum/sucking and thus a pressure differential.

Velocity stacks in an ICE are a flow conditioner more than anything, it’s about minimizing losses where atmosphere or a larger volume of air, as it enters a duct. They are also not to be seen in isolation, and they are just a visible portion of the duct that starts at the valve seat and ends at the stack. This doesn’t even get to the wave parts of it.

Velocity stacks are used on turbo props like helicopters and other slow moving aircraft. They are used because they accelerate airflow with fewer losses. In HVAC systems, converging ducts are used to accelerate air flow. In Turbofans, the bypass region is a converging duct which accelerates the flow. Ducted fans with a bell mouth inlet are more efficient, period. The diffuser on the 2022 cars are also converging ducts, IE venturi tunnels, same as they use in carburetors. By your logic the venturi tunnels in F1 cars shouldn't work because the venturi principle only works on carburetors?

When a car moves through the air, the moving car causes air to accelerate through the body work. In the case of a car moving through the air, the car is moving faster than a sprinting cheetah at all times, and thus creates a pressure differential.

They’re used on intakes because an incredible amount of the air consumed is drawn in from the sides and some from the rear of the intake radius edge. They also condition the air to flow more efficiently in a duct. They’re just transitional pieces.

Accelerating the air, slowing down, and reaccelerating like a carburetor in an intake tract is why they have larger pumping losses than an injected set up where you typically taper to one point. Maybe that’s in the port or maybe that’s at the valve seat.

A good bell mouth doesn’t add anything, it’s about mitigating losses.

[JordanMugen]

Reminds me of mid 1990's CART cars:
https://cdn.crash.net/styles/article/s3 ... k=eZN-hoK9

I remember Champcars looking so big and heavy compared to F1 cars at the time with their big 720mm rear tyres, 750kg kerb weight and 2m car width... Whoops!

[johnny comelately]

if this has been already posted, my apologies
first class analysis

[johnny comelately]

the new regulations correlating with this video by Nico Rosberg and his father at 10:10

[PlatinumZealot]

What you have written is not strictly correct. A pressure differential must occur for the velocity to increase. In the case of an ICE, The piston is creating a substantial vacuum/sucking and thus a pressure differential.

Velocity stacks in an ICE are a flow conditioner more than anything, it’s about minimizing losses where atmosphere or a larger volume of air, as it enters a duct. They are also not to be seen in isolation, and they are just a visible portion of the duct that starts at the valve seat and ends at the stack. This doesn’t even get to the wave parts of it.

Velocity stacks are used on turbo props like helicopters and other slow moving aircraft. They are used because they accelerate airflow with fewer losses. In HVAC systems, converging ducts are used to accelerate air flow. In Turbofans, the bypass region is a converging duct which accelerates the flow. Ducted fans with a bell mouth inlet are more efficient, period. The diffuser on the 2022 cars are also converging ducts, IE venturi tunnels, same as they use in carburetors. By your logic the venturi tunnels in F1 cars shouldn't work because the venturi principle only works on carburetors?

When a car moves through the air, the moving car causes air to accelerate through the body work. In the case of a car moving through the air, the car is moving faster than a sprinting cheetah at all times, and thus creates a pressure differential.

The 2022 diffusers are not bell shaped-though, Mr. Sprinting cheetah. The peak suction parts are two concave steps.

Did you teach yourself fluid mechanics, Goldie?

[djos]

if this has been already posted, my apologies
first class analysis

His analysis of the double T tray is fascinating.

[godlameroso]

Velocity stacks in an ICE are a flow conditioner more than anything, it’s about minimizing losses where atmosphere or a larger volume of air, as it enters a duct. They are also not to be seen in isolation, and they are just a visible portion of the duct that starts at the valve seat and ends at the stack. This doesn’t even get to the wave parts of it.

Velocity stacks are used on turbo props like helicopters and other slow moving aircraft. They are used because they accelerate airflow with fewer losses. In HVAC systems, converging ducts are used to accelerate air flow. In Turbofans, the bypass region is a converging duct which accelerates the flow. Ducted fans with a bell mouth inlet are more efficient, period. The diffuser on the 2022 cars are also converging ducts, IE venturi tunnels, same as they use in carburetors. By your logic the venturi tunnels in F1 cars shouldn't work because the venturi principle only works on carburetors?

When a car moves through the air, the moving car causes air to accelerate through the body work. In the case of a car moving through the air, the car is moving faster than a sprinting cheetah at all times, and thus creates a pressure differential.

The 2022 diffusers are not bell shaped-though, Mr. Sprinting cheetah. The peak suction parts are two concave steps.

Did you teach yourself fluid mechanics, Goldie?

You always teach yourself, no one is going to touch your forehead and give you knowledge, you have to want it. The tunnels are very interesting devices, the part after the strakes constricts, in typical venturi tunnel fashion. That part, leading to the throat is a converging region. How else are you supposed to speed up the airflow? Especially when the strakes acting like divergent ducts only serve to slow down the airflow as it enters the tunnels.

You know what also raises pressure while accelerating air? An axial compressor. The spinning rotor accelerates the air, as the vanes are shaped like converging ducts, and the stator vanes are shaped like diverging ducts slowing the air. The shape of the compressor is converging at each stage, this helps accelerate the compressed air in each successive stage.

[Vyssion]

Air behaves very predictably, it does pretty much what I think it does, maybe you just don't understand, and it causes you to get defensive. You do this in a lot of your posts.

It does not. Because it doesn't, this is why still in 2022 everyone from F1 teams to Boeing / Airbus still struggle with correlation between CFD / wind tunnel / and real life. Sure, you can guess on a macro level, but imaging what radiused velocity stacks will do in the inside corner of the wing is a huge stretch.

While not an aerodynamicists, a retired PhD aerodynamicists friend likes to walk around the paddock at historic events and point out that "air doesn't do that" on a lot of cars. This from an era when they were just imagining what air was doing or even rudimentary wind tunnel work.

My defense comes from wanting good, sound technical information shared on this site, and positioning your imagination as physics is not it, and I think it's totally fair to call you out on it, so others who don't know, learn fact from fiction.

Enlighten us then. Somehow an F1 car violates the laws of physics and diverging subsonic ducts don't slow down air?

Because that's the low pressure side of the wing, accelerating air lowers it's pressure, lowering the pressure in the low pressure side means more wing performance. I can't make it any simpler than that.

Your theory hinges on the wing is in isolation and it's likely not. I think you're just making things up.

It's not a theory it's simple physics. It's obvious the rear wing will suffer detachment issues, especially at low speed. I've seen designs like that on R/C craft. Similar Re#'s similar results.

There's no bodywork in front of that section of the wing, so nothing upstream can affect it. Maybe having a rear wing less prone to stalling will ruin the downforce from bodywork behind the rear wing?

Alright... I think I'm gonna step in here...

What Godlameroso is suggesting, is that the physics of, effectively, a venturi-duct which was positioned at the curved merger of the underside of the main element of the rear wing and it's endplate, would improve performance by locally speeding up the air in that region, and help prevent separation. Correct?

Hoffman, and others, are disagreeing that this would actually be a net positive effect, citing that one cannot simply [walk into mordor] place something akin to a venturi-duct onto an aero-part and expect it to magically ONLY do what a theoretical venturi-duct would do, and nothing else -- in and amongst some of the other comments made in the back and forth.

So, I have a few comments to make here, and I will also correct some misnomers I saw in people's posts with the right definitions of the physics going on:

• Although sophisticated modelling is required in order to accurately predict aerodynamic performance, contrary to what has been said prior in this discussion, it is possible for an experienced aerodynamicist to "predict" how air would react over a given surface... You need only ask yourself whether a senior aerodynamicist would be able to sketch out a "better aero package" than a junior aerodynamicist in a single design iteration... personally, I believe this to be the differentiating factor between "good" and "great" aerodynamicists

• The effect of the curved-inlet shaping which is used in ducted fans, carboretors, etc. works due to a phenomenon called the "coanda effect". However, there is some conflation going on in the thread. The effect refers specifically to the fact that if a body of moving air is close to ANY surface, then the side of the moving air closest to that surface, will cause the air between it and the surface to entrain and move out the way, creating a lower pressure than the ambient pressure around the jet. This then causes a pressure differential across the moving body of air, and so it will bend down to travel along the surface. The surface does NOT need to be curved for this to happen.

• The reason that we see it most commonly with curved surfaces, is because if you took discrete "steps" to approximate a curve (think rudimentary differentiation of a graph), each infinitely small change in direction of the surface causes that same bending as I described above. That is why curved surfaces are better to observe the effect. The deflection of the moving body of air downward, causes an equal and opposite force on the surface upward; i.e. one of the many mechanisms by which lift / downforce can be created.

• The effect of speeding up the air, is the venturi effect - not the coanda. And all this effect states is that, due to mass conservation, when air moves through a constricted section, there is an associated pressure drop that occurs. The static pressure decreases, according to bernoulli's principle, whilst the dynamic pressure increases, due to the velocity increasing according to mass continuity. Any increase in kinetic energy that you would "think" the fluid would gain, is therefore balanced out by the drop in pressure. Also, the diffuser of an F1 car only refers to the expanding region right at the back of the floor aero... it isn't a converging duct at all, because it's job is to slow down the air back to something akin to freestream, after the acceleration of it under the car to achieve a pressure drop below the car, generating downforce.

• As an additional note, if ever the constricted section expands, there is always some level of turbulence (however small or large) which arises -- and that is why when you test this sort of thing, you compare the pressure at the entrance of the system, to the constricted section; rather than the output section.

• With that said, this "theorem" only holds for a CLOSED SYSTEM. So when it comes to external aerodynamics, it just plain old "isn't that simple".

• The notion that "it is obvious that the rear wing will suffer detachment issues, especially at low speed" just is flat out wrong, and the simple reason for it is that there is no way the part would be designed, checked, approved, and sent to manufacture if that were likely to be it's main operating condition. If anything, that would imply the entire FIA and all the F1 teams' aero departments were incompetent at analyzing a wing. Also, although in theory you could have a scale RC model with similar Reynolds number to the rear wing of an F1 car, either you'd have to not make it very "scale" in the first place, or be going pretty damn quick to match it...

• The comment stating "There's no bodywork in front of that section of the wing, so nothing upstream can affect it." is once again, completely wrong -- there is an entire F1 car ahead of the rear which practically destroys the airflow that hits it!! You cannot look at something from the front and state something like "I can see the rear wing which it means air hits it cleanly" because, as I detailed above with the coanda and venturi effects, there are a myriad of parts all over the car which exert some kind of pressure influence to the air around the car. Those pressure influences are going to have a slightly lesser effect on air a bit further away, and so on... In aerospace, you need to consider the "downwash" that the main wing generates to the bulk of air ALL around it (not just the stuff right on the surface), because it changes the angle of attack of the air which hits the tail (which you use for stability) -- meaning that you could be cruising at a 0° incidence, but your tail could be seeing a -3° incidence due solely to the main wing deflecting and "coanda-ing" air downward.

• If I were to guess (and although this is an educated one, I still may very well be wrong as I've not looked at it in CFD yet...) what is going on in that slightly raised up corner/edge of the wing+endplate region, I am reminded of the tunnels on the front wing sure... but there is no footplate and gap to the road to allow for air to flow into that, forming a vortex, and then blasting the front tyres to shut down the intensity of the vortices thrown off by the front wheels. So I think back to how in the previous car's wings + endplate joints, there used to be a series of very small wing elements that formed the joint, instead of terminating the two elements directly into the endplate. If my memory serves me well, I am pretty sure that these were a way to promote upwash in that region, such that when the DRS would operate, the dynamic motion of the part (and thus the air around it) would be more controllable and less prone to separation, and probably the hysteresis which came with it. Looking at the local curvatures vs. the rest of the wing, my guess would be that they are doing something similar there again. Perhaps @jjn is sitting here reading this excitedly ecstatic about our next CFD sim project... though he could very well be shaking his head in disgust at me borking up an aero-comment too... gimme a break mate, it's 1am k thx

• To add my own thoughts on the idea of placing a venturi-like-duct in that area, absolutely not. Once again, the very presence of the object -- whether or not it functions in its intended manner or not -- will serve to disrupt the airflow more than it would ever stand to gain. There are a few reasons of the top of my head; one being that when you measure the lift/downforce of a wing, the "main proportion" of the pressure differential which is generated, comes from the pressure drop on the suction side of the wing, and not from the higher pressure on the pressure side. Again, it comes down to what you can achieve with surface curvature; and so any obstruction or object placed there, will be disrupting the airflow on the suction side (which is doing most of your lift/downforce generation), it will be throwing off it's own turbulence or interaction effects onto that suction side, the airflow on the suction side of a wing is much more important to keep clean and attached than the pressure side, and you are also reducing the surface area of the suction side with something that is lift neutral... All of these things, to say nothing of whether or not the inlet would even work given the dynamic airflow it would see after the entire car has disturbed the air already before it would enter it, makes me confident that any benefit that the venturi-duct would offer in isolation would be substantially outweighed by its negative impact on everything else that's going on in that region of the rear wing.

• Finally, the biggest trap which I see budding aerodynamicists (and a lot of engineers in general to be honest with you...) fall into, is the assumption that "if it works in isolation, all I have to do is smush it together and I'll design a mega-super thing with all the bestest bits together!!" You need only look at the eVTOL industry to see what I mean... companies which clearly know what they are doing, have sound designs... whereas relatively immature/new companies and their concepts often have ducted rotors, rotors in the wings, collapsible rotor blades that trail behind the aircraft when not in use, and all manner of other "exotic" futuristic sci-fi stuff... All things which in isolation do legitimately offer a potential improvement... but in reality, are either impossible to control at the level required, have a large penalty when it comes to extra surface area which dominates the form drag at high cruise speed, or is so mechanically complicated that the weight penalty would outstrip any aero gains in the first place, or alternatively the safety/risk levels possible in the design with today's materials would never be certifiable with the authorities.

Phew... That ended up being a lot longer than I thought... but, to the comment made a couple pages back wanting good, sound technical information shared on the site, I hope that I have managed to satiate that desire a little here

I am going to go back over the conversation and decide how I want to moderate it (I will definitely be removing some votes which I think are clearly unnecessary) but for now, I hope this post serves to "moderate with a technical spin" as was my remit when I took up the mantle.

[djos]

Thank you! Nice to see such a well reasoned deconstruction of a certain illogical argument being presented!

[jjn9128]

I'm just thrilled you say we might do more CFD. I need to pull my finger out now there are things to copy

[Stu]

One thing that I am pleased that I am seeing (although I am not sure how they are getting it past the rules on the lower rear edge of elements having an upward inclination over the last 40mm..), is that the three cars we have seen so far are using the forward element of the front wing structure as a flow conditioner for the remaining three elements and the underfloor.
This is something that I suggested would be a good thing some time ago, I just couldn’t get past how it could work within the rules on the wing profiles.
In these constructions the second element is actually working as the ‘primary’ element (or main spar) for downforce production, with the leading element there to control the flow structure into the underfloor and front wheel ‘bodywork’.
Also interesting is the similarities between the McLaren and Aston adjustment structures, they are both using a vertical ‘fin’ at the inner part and an outwashing structure for the outer part; the only difference is that it appears the Aston has two adjustable flaps, whereas McLaren are only adjusting one.
I’m also really pleased that we are seeing different sidepod designs, it is going to be really interesting to see which idea is actually best!!

[mzso]

I think its always worth pointing out that the air from the radiators is always very low energy air: it has had to pass through the radiators after all. As such you always want it to be as far away as possible from any sensitive areas such as the tyre squirt area.

May be a silly question, but didn't anyone try to engineer out those windcatcher radiators? And blending the cooling inside the car's skin, with all that high speed air flowing over it?

In the style of the Brabham BT46? I'd be amazed if they could get sufficient heat transfer.

I guess. But that had to have a radiator somewhere.
Well, my thinking is that there is a lot of air, and a lot of surface. It might be possible to make it work, and gain aerodynamically.
You wouldn't have a small stack of lamellas. You'd have a large smooth surface, maybe with added waviness or fins that the underside already has.

[NicoS]

will we see sidepods like this Jordan 195?

[cooken]

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.