General aero discussions

[johnny comelately]

Also, you will have losses when you have viscous walls - due to the boundary layer effect - even if its a flat plate, but these are negligible compared to the separation

Plot Po/Po_infinity and the losses can be visualised as well.

Is there a chance you could put up a graph/picture of this please (aero for dummies )

You can see this in any aero engine intake flows/distorted regions of flow. Dont have an automotive aero pic

OK thank you

[godlameroso]

Is there a chance you could put up a graph/picture of this please (aero for dummies )

You can see this in any aero engine intake flows/distorted regions of flow. Dont have an automotive aero pic

OK thank you

https://cerfacs.fr/wp-content/uploads/2 ... rderie.pdf

Here you go my good man. This is one of the better papers regarding visualizing axial compressor separation losses.

[johnny comelately]

You can see this in any aero engine intake flows/distorted regions of flow. Dont have an automotive aero pic

OK thank you

https://cerfacs.fr/wp-content/uploads/2 ... rderie.pdf

Here you go my good man. This is one of the better papers regarding visualizing axial compressor separation losses.

Ah, very good
Thank you

[ringo]

The undercut has more importance than the flanks of the sidepods.
The flanks channel air toward the rear, and improve pressure recovery. That was what the alpine was doing last year.
I am a critic of the whole tyre wake theory, and I think we are seeing that play out now with the new cars.
The size of last years pods seemed more to do with having a big upper surface for pressure recovery, moreso this tyre wake thing that was being bandied about last year.
As said in the mercedes thread, the MP26 inner channel, similar as well to the Alpine last year, is what we are seeing play out.

[Andi76]

The undercut profile is quite similar to the RB18

It looks like the trend is to merge the Ferrari bathtub with the Red Bull's "ramp-down" sidepods and spice this up with a Ferrari sidepod inlet and then add other Ferrari or Red Bull like solutions as required. But clearly Red Bull and Ferrari 2022 have set the trends for the future and had the best solutions.

I agree to a certain extent but you cannot rule out "big 3 bias".

In spite of all these teams running supposedly "RB or Ferrari" inspired designs, they were and will still be behind Mercedes. Miles behind.

That may well be the case. However, it wasn't like that at the beginning of the 2022 season. Also, the times are over where a team like Mercedes could simply throw money at a problem and stay ahead due to these much greater resources. Considering this fact and that at the moment in no way white Mercedes does, such a statement is somewhat presumptuous and one can possibly also be quite quickly off the mark. Williams fans made similar statements 20 years ago, or McLaren fans a little more than 10 years ago. History proves that it is by no means a fact that the "big three" or "big four" (as it was in the 90s and early 00s) are immune from falling behind. In Formula 1 it is enough to bet on the wrong horse for one or two years to fall behind technically. And there was no budget cap yet...

The undercut has more importance than the flanks of the sidepods.
The flanks channel air toward the rear, and improve pressure recovery. That was what the alpine was doing last year.
I am a critic of the whole tyre wake theory, and I think we are seeing that play out now with the new cars.
The size of last years pods seemed more to do with having a big upper surface for pressure recovery, moreso this tyre wake thing that was being bandied about last year.
As said in the mercedes thread, the MP26 inner channel, similar as well to the Alpine last year, is what we are seeing play out.

The undercut has more importance than the flanks of the sidepods.
The flanks channel air toward the rear, and improve pressure recovery. That was what the alpine was doing last year.
I am a critic of the whole tyre wake theory, and I think we are seeing that play out now with the new cars.
The size of last years pods seemed more to do with having a big upper surface for pressure recovery, moreso this tyre wake thing that was being bandied about last year.
As said in the mercedes thread, the MP26 inner channel, similar as well to the Alpine last year, is what we are seeing play out.

"Tyre-wake theory? Managing the front-wheel-whake has been something F1 engineers have been working on more than anything else for over 30 years. I don't know if I'm understanding you correctly - but it's not a theory, it's a fact that this is critical to the aerodynamic performance of an F1 car. Just as it is a fact that larger sidepods create a flowfield that is superior to that of zeropods in this respect. At least according to the current rules with the missing bargeboards.It is therefore no coincidence that not a single team has copied Zeropods, but on the contrary has moved away from this or similar solutions as quickly as possible (McLaren, Williams). Tyre Wake Management is a much bigger factor than the help for pressure recovery, because bad front wheel wake management destroys a lot especially in this area. And the fact that not a single team(except of Mercedes maybe) even begins to move in this direction speaks for itself.

[ringo]

Let's not discuss this here.
But i think you are misunderstanding what I am saying.
The broad sidepods have little to do with front tyre wake.
The undercut from the tea tray to the underneath of the sidepod is the main aerodynamic feature of the formula. And this has more to do with the underfloor from midspan of the car to the rear tyre.

oh I just realized the discussion was moved!

Yes let's discuss this here.

I would love for a 3d model to be shared for me to run the cfd.
If there are no sharers i can do a very rudimentary model in about a week.

But the front tyre wake is not particularly manipulated by the bluff body of the sidepods to do anything special.
If i were to entertain the theory, at best i can see this low pressure and disorganized flow region colliding with the big sidpod then given some "form" as it adheres to the pod. But this is draggy.
The true function of the big pods what what they do with their upper surfaces as it relates to pressure recovery towards the diffuser, providing higher pressure and cleaner flow on top of the diffuser and through the small crevaces between ream arms, beam wing and gurney on the diffuser trailing edge.

Now lets look on the barged boards that are no longer on this new formula. These were responsible for diverting air from between the front tyres, from the front wing, and some of what is left in the wake of the front tyres.
They pushed the air outward, but importantly pulled and expanded air behind them atop of the floor. The air that's pushed outward also educted air from underneath the foor, which acts to drive air flow under the floor.

Without bargeboards, this function is carried out by the underneath of the sidepods themselves, otherwise called the undercut. See new AMR23 front view. The function takes place further downstream midrift of the car. Drives air from underneath increasing the efficiency of the floor. Maybe there is some benefit for the lower quarter of the rear tyres in terms of drag reduction, but I am not certain until i see or do some proper cfd on it.

[godlameroso]

Not true, there is a bargeboard, the outer floor fence acts as a bargeboard and is far closer to the wheel than the sidepod undercut. Every single car has the outer fence as a bargeboard, furthermore you completely ignore the furniture on the wheel itself. There are 2 flow deflectors on the inner lower half of the wheel, one on the leading edge and another on the trailing edge. Combine the flow from the front wing, the furniture on the wheel, and the outer floor fence, and you have 4 different flow surfaces to outwash air from the inboard side of the wheel. None of this is conjecture, they are physical parts on the car.

Outwashing air from the inboard side of the wheel is the same as if the wheel were toed out and extreme amount. The more the outwash angle relative to the direction of motion, the more the airflow around the tire behaves as if the tire were toed out.

Outwash at the tire organizes the wake into a vortex which in turn reduces tire squirt. Call it a theory, but Ferrari, Haas, Aston Martin, Williams, seem to be on board with it.

Acura is on board with the theory as well it seems, and it paid off this Daytona 24.



They're the only GTP car with that outwashing slot behind the rear tire, now I'm not saying that's the only reason they won, but it sure didn't hurt them.

[godlameroso]

https://www.nature.com/articles/s41598- ... 0stability.

"The hot wall is opposite to the cold wall, the transition region moves backward and the laminar flow range increases. While the lower airfoil is under the influence of the forward pressure gradient, which is similar to that of the upper airfoil due to the wall temperature gradient, and the effect of laminar flow range is more obvious. Temperature gradient not only affects the transition behavior of the laminar boundary layer, but also affects the friction coefficient in turbulent region, which shows apparent variation law with wall temperature."

"Wall heating increases the transition Reynolds number and delays the transition. When the control temperature increases from 292 to 500 K, the transition Reynolds number increases by approximately 28%."

"Higher wall temperature reduces Reynolds shear stress and turbulent kinetic energy in the boundary layer, that is, the hot wall suppresses the tangential and positive pulsation and stabilizes the flow. Therefore, the wall heating control delays the transition from laminar to turbulent flow, increases the transition Reynolds number and enlarges the laminar flow region."

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.

[Vanja #66]

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.

[godlameroso]

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.

[beschadigunc]

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.

TBH LBM is pretty poor for predicting race car airflows. at the real air doesn't behave that way. To see compare with DNS simulations

[godlameroso]

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.

TBH LBM is pretty poor for predicting race car airflows. at the real air doesn't behave that way. To see compare with DNS simulations

DNS simulations take super computers my guy. Especially of something that big and complex. Hell DNS solvers are usually done on 2d sections of airfoils. LBM is the future, it's already so promising with so little development, that once its issues are sorted DNS will become a dinosaur.

DNS also has limitations, real air is not computer graphics, so I'll give you that.

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

[Hutchie.91]

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

That's not how physics work. You can't describe something's characteristics with a vague blanket statement like that when the thing that dictates turbulence depends on a lot of factors, of which a subset we like to observe and analyse on earth may be mostly turbulent behaviour, does not mean that is air's intrinsic property when observed in it's singularity throughout our universe

It's like saying sound is loud or hydrogen is hot because that's what we see when observing the sun.

[Vanja #66]

Other than pretty colours, that particular simulation is useless. Model is a 3D printing small scale model with thick edges etc. Domain is way too small, wheels aren't turning, solver method is inadequate. The result is according to the old one - shiet in, shiet out.

There is absolutely no scenario where such an extensive amount of turbulence can happen in free stream airflow. Just because a simulation requires an insane amount of computing power and complex solvers doesn't make it worth doing, as those videos so clearly demonstrate.

Air doesn't turn more than 15 deg per surface? You do know just after the stagnation point of aerofoils the air turns 90 deg up and down? You do know stagnation point on aerofoil at higher angle is on the pressure side, making the air that goes over the suction side actually turn more than 180 degrees?

[ringo]

Not true, there is a bargeboard, the outer floor fence acts as a bargeboard and is far closer to the wheel than the sidepod undercut. Every single car has the outer fence as a bargeboard, furthermore you completely ignore the furniture on the wheel itself. There are 2 flow deflectors on the inner lower half of the wheel, one on the leading edge and another on the trailing edge. Combine the flow from the front wing, the furniture on the wheel, and the outer floor fence, and you have 4 different flow surfaces to outwash air from the inboard side of the wheel. None of this is conjecture, they are physical parts on the car.

Outwashing air from the inboard side of the wheel is the same as if the wheel were toed out and extreme amount. The more the outwash angle relative to the direction of motion, the more the airflow around the tire behaves as if the tire were toed out. https://files.catbox.moe/mve01e.jpg

Outwash at the tire organizes the wake into a vortex which in turn reduces tire squirt. Call it a theory, but Ferrari, Haas, Aston Martin, Williams, seem to be on board with it.

Acura is on board with the theory as well it seems, and it paid off this Daytona 24.

https://i.i-sgcm.com/news/article_news/ ... 83_3_l.jpg

They're the only GTP car with that outwashing slot behind the rear tire, now I'm not saying that's the only reason they won, but it sure didn't hurt them.

The vane on the edge of the floor is not enough to divert front tyre wake. Also the cfd you posted has not front wing.
Not to say what you are saying does not have some truth to it, but its scale and impact which is misleading.