General aero discussions

[beschadigunc]

So how does air behave? It's not mostly turbulent? News to me.

PIV images from ground research wind tunnel Experiments are the best way to visualize. What LBM shows is really not realistic

[ringo]

I wonder if Ferrari is exploiting this phenomenon with their cooling outlet louvers. In essence keeping a hot wall in order to keep flow attached to the top of the sidepods for longer.

Good find and good idea to think about. In my view, no reason to think Ferrari need that effect, neither last year and especially not this year with less aggressive tub design. Other teams don't have louvres on their slopes, I find it hard to believe they have separation issues.

Separation is a given, delaying it can only help.

Air doesn't like to turn more than 15 degrees per surface, just won't do it, not without protest. Plenty of surfaces on the engine cover that exceeds that. If you want to manipulate the air over the engine cover successfully, you have to maximize your bets. It's not enough to get the shape right, you have to consider the thermals and to a lesser extent, the acoustics.

In any case, F1 cars are a big ol turbulent mess with very little actual laminar flow.



Because you're against such overwhelming opposition to your laminar goals, any small improvement can lead to significant changes.



And to boost awareness of new tech, these CFD were done using the latest and greatest Lattice Boltzmann Method.

Good videos.
I think the flow looks like this because it may be at low speed; also depends on the visualization; its not streamlines, it something else. But it does have some accuracy. The computation volume is too small though. Needs to be maybe 6 car widths wide, and 6 long.
If it were wider, you would see more vortices developing at the side of the car.
But what is of note is 40s into the first video. Watch from there and note that the wake of the front wheel goes wide, and what's actually coming through is flow from the front wing passing between wheel and monocoque toward the bargeboards.
At the rear wheels the low energy turbulent flow from the front crashes here and spills to the sides.
The question is what do you want to do here?
Do you want flow to reach the top of diffuser and beam wing?
Where will you take it from, top of sidepod, the undercut along the floor?
Since ground effect, how much more focus on underfloor tunnels and will the focus be on the front or rear?
Note the low velocity (blue).

[AR3-GP]

Air doesn't like to turn more than 15 degrees per surface, just won't do it, not without protest. Plenty of surfaces on the engine cover that exceeds that. If you want to manipulate the air over the engine cover successfully, you have to maximize your bets.

This is an oversimplification I would say. The pressure distribution around the car is what defines what the air will and won't do.

In isolation this theory of yours has some merit, but an F1 car generates a massively complicated 3D pressure field around it.The pressure distribution in one area of the car, influences the flow turning/separation sensitivity in another. It's not easy to understand without the mythical CFD eyes.

[delsando53]

I know floviz has been used to correlate with aero at the factory.
Has anyone thought of such idea , it's more dynamic and real time with the visualisation of the flow with the car ie during long straights, high speed and slow speed turns. Cameras can be set below the chassis to see the under flow.




if red smoke is visible on prying rival teams and photogrpahers , i suppose IR/flir camera to image warm air ?

[mechanoit]

With the 2022 regulations, the side pods are not so important. They are of course important for managing front tyre wake to reduce risk of disturbed flow affecting floor edge and to an extent getting high energy air to the diffuser, beam wing, rear wing and preventing energising the rear tyre squirt further and all those sorts of things.

This is incredibly contradictory. If the sidepod is used to prevent the front tire wake from entering the diffuser, then it is rather important. Furthermore, one again the proof is in the pudding. How do you explain how all teams have evolved these "unimportant" sidepods .

I'm seeing an incredible amount of sensitivity (as Andi76 pointed out) to the discussion of the Mercedes sidepods. It has become a point of pride seemingly to say nothing is wrong. People are eager to dismiss discussion of it because Mike Elliot told them so.

At the moment, it is not apparent that anyone should be taking design advice from MGP based on their success under these new regulations...one must take a step back and look at the pudding to realize this.

Mercedes had great success under the previous regulations and I would absolutely follow them off the train tracks were the regulations as they were a decade ago. But now? I'm not so sure.

Perhaps I over simplified and overstated it. Not to say that it is not important, just that the n’th degree management to maximise every last ounce from the diffuser is not as important as it was in pre-2022 regulations where the diffuser was everything regarding downforce from the floor.

Clearly front tyre wake management is important but do we really think the Mercedes doesn’t have the aerodynamic tools to model this to a high level? The most successful F1 team of all time hasn’t got its results by not having the tools to carry out basic aerodynamics. It seems to me that the floor is a different prospect altogether. New, difficult to understand, difficult to model, difficult to tune.

Mercedes understanding of side pod flow and management seems to be ok. I assume they will refine and improve in that area as they have already said so but I don’t expect very big changes. I may be of course very wrong.

[Vanja #66]

Zero pods are serving there purpose. It's clear that they have benefits over other pods and Mercedes will evolve them again.

What do you think is their purpose, as is? What would be the benefits over other designs?

With the 2022 regulations, the side pods are not so important. They are of course important for managing front tyre wake to reduce risk of disturbed flow affecting floor edge and to an extent getting high energy air to the diffuser

For the purpose of front tyre wake management, they are one of two elements that affect it. The other element are floor vanes, which are both very small and their effect very limited. You can easily have the greatest floor of the field and some wake creeps in, messes up the diffuser and on the track you are nowhere...

The other thing they clearly do is manage the floor edge vortex and flow towards diffuser mouse hole. Both have a direct influence on floor performance. So while they are not the main factor to get you to 98-99% of the leader, they could be the factor to bump you in the lead.

But this is 100% OT and unrelated to W14 specifically.

The most successful F1 team of all time hasn’t got its results by not having the tools to carry out basic aerodynamics.

Ferrari reference in W14 thread? Now I've seen everything

[NoDivergence]

Now if you had bothered to compare the time, you would have noticed that I wrote all this 4 hours before the judges' article even appeared.

But it doesn't matter anyway, because I'm off the topic again, because as far as that goes, it's more like kindergarten here - as soon as the topic comes up that zerpods are the reason for certain disadvantages, personal attacks and other things follow.

And I don't remember anyone at Mercedes saying that they are gradually turning away from the Zeropods...why would they do that when it has no impact on performance and is a concept that promises superior downforce (which in itself is a contradiction in terms)?

I concur that here must be an impact on performance, or else teams wont spend so much time shaping them. I think that in itself is undeniable.
I think the issue is if the sidepods are the source of aerodynamic problems. This is the contention most have especially with the lack of real evidence.
It seems that, based on Elliot's words, the zeropods will evolve over the season.

If they are changed I will hazard a guess of a blend of MP4-26, Ferrari 641. Just a wild guess based on their philosophy. I am thinking low slung side pods with vertical openings near the body, but bluff body lumps outboard to sheild from the wake while providing a low gully towards the diffuser.

That sounds like a possible solution. Of course, you'll never know for sure if the side boxes are to blame. Even the teams, despite their resources and expertise, have a hard time determining the exact trigger. But I think that if the very team that is the only one to have such sidepods obviously has aerodynamic problems on both models, then that at least strongly suggests it. Add to that what other teams have said about the complexity and control of the vortex and the indicators of more difficult management of both the top and lower front wheel wake and its detrimental effect on underbody performance, and I think it's fair to say that there is some evidence to suggest that.

But strong indicators or not - it is a topic on which some people here react sensitively and do not want to hear. And for this reason and also because it remains of course finally a theory, which can be just as well wrong, as so much other also what we do here and about what we talk, I withdraw from this topic again. The final proof will come. If Mercedes actually deviates from the concept, it should be proven.

Why the constant need to twist our words? Haven't you guys had enough of that? No one was saying W13 zeropods were the predominant cause of bouncing, it was clear as day W13 initial floor was way too aggressive compared to RB and Ferrari and they had to dial it down with Barcelona upgrade. It was an improvement, but when they tried to lower the car back to intended ride height problems started re-occurring, coupled with flapping floor in the rear. Don't tell me the diffuser throat section movement doesn't affect floor performance




Simulations are better than ever today, users are also better than ever with input and proper settings. It's only going to get better still. I did a race car CFD with two software and correlation in WT, 1% error on downforce and 2% error on drag. And that was 7 years ago. On the other hand, the geometry of these cars is simpler than any since 2009 and even then the Y250 vortex and double diffusers were a headache for any meaningful prediction that very same year. Aerodynamics are not sorcery and witchcraft, they can be understood to great extent even when you are not in an F1 team. That's what we are trying to do here.

By the way your CFD lacks enough detail to draw any conclusions.
We should be seeing a storm of vortices in those areas that you focus on to draw your conclusions. Instead you show a few strands of stream lines.
It's a welcome effort to visualize. But I can bet if you change the boundaries, change the wind speed, or even increase the mesh and ran over the simulation, the results will not be the same.
You can easily paint any picture you wish with your simulation, once you are not sharing the preparation and the numbers.
So your opinion and your results are as good any one elses opinions on the forum once they have enough experience.

Any engineer knows what CFD stands for ;colors for directors

Unless you get a lot of time and resources, CFD will say not much.
.

I don't think that Vanja claims that his simulations are completely accurate and fully meaningful. On the contrary, he always emphasizes that they are not. They are there to provide general insight into the goals and effectiveness of the changes. And in this regard here they are quite meaningful and well suited for this and say quite something .That he takes the trouble to do this is immensely enriching. His CFD simulations are even used by former F1 aerodynamicists. Instead of criticizing his simulations, we should accept and honor them, and not say that they are no better than a mere opinion of anyone halfway experienced in this forum. Otherwise we will soon have to do without it, because I don't think anyone will continue to invest so much effort if there are people who don't appreciate it. So I ask you - if you don't appreciate it and think you are so good that you can see with the naked eye what is visible on these CFD simulations - I am not and many others are not. So don't destroy it for us who don't have this gift and appreciate these CFD simulations very much and that makes this forum stand out even more from all the others.

CFD is the same as any analysis tool. Garbage in, garbage out. Wrong boundary conditions give wrong answers.

In this circumstance, Vanja is trying to isolate sidepod concepts as performance differentiators, even to the point of calling out drag percent deltas in the past.

Essentially, he is trying to utilize this model like a submodel. Only problem is, the flow is jacked up because A, the front wing (airfoil geometry, planform and twist geometry, endplate, etc)/nose/suspension geometry does not match the real car whatsoever, it's based on the default base model from two years ago. B, detail optimization can easily be more than 5% drag anyways.

As far as Vanja's reply to this

In any case, it's clear their sidepod concept is in fact the problem, not only for floor structural instability (that seems to have been solved with wider sides) but also for actual aerodynamic instability and unpredictable interaction with other elements. I was convinced they were very thorough about it last season...

Being that his response is

Why the constant need to twist our words? Haven't you guys had enough of that? No one was saying W13 zeropods were the predominant cause of bouncing, it was clear as day W13 initial floor was way too aggressive compared to RB and Ferrari and they had to dial it down with Barcelona upgrade. It was an improvement, but when they tried to lower the car back to intended ride height problems started re-occurring, coupled with flapping floor in the rear. Don't tell me the diffuser throat section movement doesn't affect floor performance

It's like having whiplash because contradictions are everywhere. The narrow SIDEPOD CONCEPT does not have anything to do with the flapping floor.

Also, very impressive that Vanja's CFD correlated well to windtunnel. That's what every team in the paddock is saying about their components. There's not going to be a single team that will put parts out of the autoclave without good correlation between CFD and tunnel. The problem is when you put it on a car and it doesn't behave like you expect. This happens all the time. Just look at WTAC unlimited class and there's always things that don't work like expected.

Structural is even easier to get correlations than aero. And even then teams are breaking parts on cars.

[Vanja #66]

In this circumstance, Vanja is trying to isolate sidepod concepts as performance differentiators, even to the point of calling out drag percent deltas in the past.

Essentially, he is trying to utilize this model like a submodel.

Like ringo, I can only suggest you read the disclaimers first

[mechanoit]

Zero pods are serving there purpose. It's clear that they have benefits over other pods and Mercedes will evolve them again.

What do you think is their purpose, as is? What would be the benefits over other designs?

With the 2022 regulations, the side pods are not so important. They are of course important for managing front tyre wake to reduce risk of disturbed flow affecting floor edge and to an extent getting high energy air to the diffuser

For the purpose of front tyre wake management, they are one of two elements that affect it. The other element are floor vanes, which are both very small and their effect very limited. You can easily have the greatest floor of the field and some wake creeps in, messes up the diffuser and on the track you are nowhere...

The other thing they clearly do is manage the floor edge vortex and flow towards diffuser mouse hole. Both have a direct influence on floor performance. So while they are not the main factor to get you to 98-99% of the leader, they could be the factor to bump you in the lead.

But this is 100% OT and unrelated to W14 specifically.

The most successful F1 team of all time hasn’t got its results by not having the tools to carry out basic aerodynamics.

Ferrari reference in W14 thread? Now I've seen everything

Agree with all above, with maybe the exception of the Ferrari reference, but regardless well played Sir, well played!

[Andi76]

With the 2022 regulations, the side pods are not so important. They are of course important for managing front tyre wake to reduce risk of disturbed flow affecting floor edge and to an extent getting high energy air to the diffuser, beam wing, rear wing and preventing energising the rear tyre squirt further and all those sorts of things.

This is incredibly contradictory. If the sidepod is used to prevent the front tire wake from entering the diffuser, then it is rather important. Furthermore, one again the proof is in the pudding. How do you explain how all teams have evolved these "unimportant" sidepods .

I'm seeing an incredible amount of sensitivity (as Andi76 pointed out) to the discussion of the Mercedes sidepods. It has become a point of pride seemingly to say nothing is wrong. People are eager to dismiss discussion of it because Mike Elliot told them so.

At the moment, it is not apparent that anyone should be taking design advice from MGP based on their success under these new regulations...one must take a step back and look at the pudding to realize this.

Mercedes had great success under the previous regulations and I would absolutely follow them off the train tracks were the regulations as they were a decade ago. But now? I'm not so sure.

Perhaps I over simplified and overstated it. Not to say that it is not important, just that the n’th degree management to maximise every last ounce from the diffuser is not as important as it was in pre-2022 regulations where the diffuser was everything regarding downforce from the floor.

Clearly front tyre wake management is important but do we really think the Mercedes doesn’t have the aerodynamic tools to model this to a high level? The most successful F1 team of all time hasn’t got its results by not having the tools to carry out basic aerodynamics. It seems to me that the floor is a different prospect altogether. New, difficult to understand, difficult to model, difficult to tune.

Mercedes understanding of side pod flow and management seems to be ok. I assume they will refine and improve in that area as they have already said so but I don’t expect very big changes. I may be of course very wrong.

I recommend Willem Toets (Ex-Benetton, Ex-Ferrari, Ex-BAR, Ex-Sauber Head of Aerodynamics) latest lecture at the University of Bolton(available at youtube) where he puts forward a theory why Mercedes might actually struggle in the wind tunnel to notice certain effects that happen in reality. It's a theory, but a very plausible one, put forward a few weeks ago by one of F1's most experienced aerodynamicists.

[chrisc90]

https://www.youtube.com/live/kixMMfEQ-FA?feature=share

This one?

[Henk_v]

The used term is correlation to simulation. CFD is one of many simulation tools.

They also have models for tire wear, deg and temp. They have models for engine temperature, models for engine wear, models to model the model trophywifes, you name it.

[taperoo2k]

Out of interest, how long does it take to correlate with the findings of the wind tunnel/CFD without changing any parts? Surely they should be able to get to the results fairly quickly out on track compared to the computer.

The data from the car from various sensors, aero testing equipment data etc all needs to be processed.

Im sure the models on computer and physical smaller scale stuff will be fairly well detailed in both instances so it cant be that hard to run the car on track in the configuration set on the computer and compare the differences/similarities.

They'll have started the processing and analysis on the data coming from the car as soon as it hit the track on day 1.
First they have to ensure the data from the car (real world) matches the data from the simulation (virtual world) tools like CFD.

We arent talking changing hundreds of different aero parts to try and get the car to match a simulation here.

From memory an F1 car produces around 3gb of data during a race from 120 sensors producing something like 1500 data points every second. 3 days of testing, multiple race distances covered means they'll have a lot of data to get through.

As for the sidepods? If Mercedes get them to work and if they see the team leap ahead of Red Bull then Mercedes will have been right to pursue the design philosophy. At some point if it doesn't work, then Mercedes will have to go back to the drawing board. I wasn't expecting Mercedes to be top of the F1 tree right from the get go this season.

[chrisc90]

But how many laps do you need to do in order to ensure that you have enough data to compare with your simulations though?

I mean I really cant see it taking ~400 laps on average to get enough information to compare to your runs from over the winter.

Surely it would be better to test the different setups/aero configurations your bringing then go back and compare them to your Sim work. That way you have multiple configurations to compare and a more accurate set of data of all your runs.

[AR3-GP]

Out of interest, how long does it take to correlate with the findings of the wind tunnel/CFD without changing any parts? Surely they should be able to get to the results fairly quickly out on track compared to the computer.

The data from the car from various sensors, aero testing equipment data etc all needs to be processed.

Im sure the models on computer and physical smaller scale stuff will be fairly well detailed in both instances so it cant be that hard to run the car on track in the configuration set on the computer and compare the differences/similarities.

They'll have started the processing and analysis on the data coming from the car as soon as it hit the track on day 1.
First they have to ensure the data from the car (real world) matches the data from the simulation (virtual world) tools like CFD.

We arent talking changing hundreds of different aero parts to try and get the car to match a simulation here.

From memory an F1 car produces around 3gb of data during a race from 120 sensors producing something like 1500 data points every second. 3 days of testing, multiple race distances covered means they'll have a lot of data to get through.

As for the sidepods? If Mercedes get them to work and if they see the team leap ahead of Red Bull then Mercedes will have been right to pursue the design philosophy. At some point if it doesn't work, then Mercedes will have to go back to the drawing board. I wasn't expecting Mercedes to be top of the F1 tree right from the get go this season.

There's a caveat.

This regulation cycle only last through 2025 after which the cars will change again.

A concept is no good if it takes 2-3 years into a 4 years regulations cycle to make it work. Sure it might win out in the end, but did you really win when a simpler, "inferior" concept from your POV won 3 out of 4 titles before you finally got your concept to work?

Whats that saying?

A bird in the hand is worth two in the bush.