2017-2020 Aerodynamic Regulations Thread

[turbof1]

This will be part of the upcoming part 2: optimisation of the endplate

[Just_a_fan]

I wonder how much effect the few mm on one side or the other will have on the resultant flow. I guess it all helps.

I would guess that the teams will be furiously working on a device(s) to go in the barge board area to help push the front tyre wake away. It won't be as effective as the front wing, presumably, but if it helps to keep the underfloor air "clean" then it's going to be a big performance item. Obviously, part of the barge board function is to help with front tyre wake management but it seems like it's going to be doing it all on its own from now on.

Any thoughts yet as to how much performance the teams will lose from the front wing changes? Also, will there be a noticeable balance shift forwards with the new front wing? I would think that the wider wing that is only wing (and therefore is all about downforce rather than flow management) and the potential loss of underbody flow quality, might lead to a forward shift. I wonder if the wider rear wing is intended to compensate for this.

[turbof1]

I wonder how much effect the few mm on one side or the other will have on the resultant flow. I guess it all helps.

Not a lot, no. Basically you are dealing with a semi-standarized bodywork piece. You take whatever is left on the table, but I wouldn't even call it crums anymore. There are maybe, emphasis on maybe, more radical ways available, one of them will be discussed in the article, but even then it's doubtful that it ultimately brings something. The endplate you see above is likely going to featured on every car next year. There's more freedom in the footplate, which says a lot.

[godlameroso]

Footplate being under the endplate? Ie the triple stacked footplate TR played around with?

[turbof1]

Footplate being under the endplate? Ie the triple stacked footplate TR played around with?

That avenue of stacking the footplate is closed off. You cannot slot the footplate anymore. The regulations give you 30mm inboard of the Virtual Endplate Surface (VES; keep that acronym in mind because it will be used constantly for the front wing regulations) and outboard the space between the VES and 1000mm from the car centre plane.

Just so we are clear: me saying you can do more with the footplate than the endplate is an indication how tight the restrictions are, even though the footplate also has more restrictions!

[jjn9128]

Any thoughts yet as to how much performance the teams will lose from the front wing changes? Also, will there be a noticeable balance shift forwards with the new front wing? I would think that the wider wing that is only wing (and therefore is all about downforce rather than flow management) and the potential loss of underbody flow quality, might lead to a forward shift. I wonder if the wider rear wing is intended to compensate for this.

No idea yet - the 1.5sec/lap quoted by the media earlier this year is a little pessimistic. It's more likely in the order of tenths.

The front wing may be bigger, but the rear wing is also bigger. The aero-balance is a relationship between the centre of pressure and the centre of mass - as the COG is still mandated by the FIA (~f46:r54 +/-1.5%) the balance will remain the same - trimmed for each track. If the front wing is producing too much downforce, trim it back and save some drag.

While they are loosing flow conditioners, the front wing and front wheels are co-dependent. The circulation at the tip of the front wing cancels some of the circulation of the front wheel - reducing lift and drag. The wing is also taller, so the upper elements near the tip may be extremely cambered to push the wake up - provided the flow doesn't separate.

I believe a wider front wing is a more efficient solution, so I imagine these front wings are going to be significantly less draggy, but I predict increased complexity around the mid-chassis to compensate the loss of flow conditioners. So total drag will end up roughly similar.

[Just_a_fan]

Thanks for the reply, that all makes sense. I had forgotten about the mandated CoG and thus, effectively a mandated CoP.

[Blackout]

Great work boys.

I have a question; Which area of the 2018 cars lose downforce the most when it follows another one? What do the drivers and engineers say? AFAIK the amount of lost DF when following, is important but it the balance shift topic is atleast as important...
AFAIK in 2016, the cars generally experienced rearward balance aero shift and became very understeery... But what about the 2017-2018 cars?

[godlameroso]

Downforce is mainly lost in the front end, but the front end is also conditioning airflow downstream, so that gets disrupted as well.

[turbof1]

Great work boys.

I have a question; Which area of the 2018 cars lose downforce the most when it follows another one? What do the drivers and engineers say? AFAIK the amount of lost DF when following, is important but it the balance shift topic is atleast as important...
AFAIK in 2016, the cars generally experienced rearward balance aero shift and became very understeery... But what about the 2017-2018 cars?

Like godlameroso said, the front gets hit first with the turbulent flow. After that, the whole car basically works on straightening the flow (well, the flow that isn't pushed outboard that is), so the effect is much less pronounced at the rear of the car (still there though).

[jjn9128]

Great work boys.

I have a question; Which area of the 2018 cars lose downforce the most when it follows another one? What do the drivers and engineers say? AFAIK the amount of lost DF when following, is important but it the balance shift topic is at least as important...
AFAIK in 2016, the cars generally experienced rearward balance aero shift and became very understeery... But what about the 2017-2018 cars?

I'm not going to disagree with what's been said per se... downforce lost will impact the laptime for the following car, but the balance shift is what the drivers really feel - it delays them accelerating out of a turn and overheats the front tyres (especially the Pirelli's). The way the cars produce downforce is the same since 1984 (front wing, rear wing, underbody with diffuser) so nothing has really changed since then.

I think this answers your question, so the rest of this post may be superfluous!!

The downforce loss, in my experience, is mostly from the result of reduced dynamic pressure owing to the lead car. By that I mean the air being dragged along behind the leading car reduces the capability for the following car to produce downforce. This Pdyn effect squeezes the static pressures on the surfaces of the following car. So high pressure regions become less high, drag is reduced, and low/negative pressure regions become less negative, downforce is reduced.

This is a scaling effect so areas of peak pressure are more greatly affected than areas where the pressure is close to atmosphere - e.g. if you have a peak of negative pressure like the front of the floor, Cp ~ -3, a 50% reduction is +1.5. If you have a large region where pressure is Cp = -1, like the majority of the underbody, that 50% reduction is only +0.5. Now 50% is quite an extreme example (depending how far behind the lead car 30-35% would be closer to the truth) but it makes a nice easy example.

There are a few peaks of negative pressure on the lower surfaces of the car (downforce), the front wing, the front bib and leading edge of the floor under the sidepods, the diffuser kick, and the rear wing. All of these are affected - the forwards surfaces slightly more so than the rear because the wake is slightly stronger (only a few percent) nearer the lead car, but the major effect for a balance shift is the front edge of the floor - as the point closest to the track surface, where the peak negative pressure is greatest. The front and rear wings will lose equivalent downforce, because of the shape the wake takes - when you slice through it transversely it is described as "mushroom" shaped, so there a large region of Pdyn deficit which affects the rear wing.

Then there is the secondary effect - which is the wake disturbs/prevents the carefully sculpted aero structures from forming. This is a biproduct of the Pdyn effect, a vortex is formed when high pressure air migrates towards a low pressure region - if those pressures fields are made weaker, the vortex which forms is weaker - so does not do the job it was designed to do down the car. This use of vortices is particularly prevalent, but not limited to, around the front wing and bargeboards.

This is all true when following directly behind - but if the car behind crosses the wake, say in a corner, driving high to low to undercut an opponent on the way out of a turn. The balance can shift from neutral, to understeer, to oversteer, and back to neutral as the wake affects different parts of the car.

IMO there are a few things affecting the ability to follow at the moment, 1) the tyres don't allow for a small amount of sliding without overheating. 2) cooling is affected to the drivers have to back off to save their engine allocations. 3) track design doesn't allow for multiple racing lines to get out of the wake and do something different (The Indian GP had a corner which worked well (T4 I think?), the Portland Indycar track did a similar thing this year).

[henry]

I like the conceptual description of the lead car dragging the air behind it.

As I understand it the current cars, with their outwash concept, the cars drag a plume considerably wider than the car width. An objective of the new regulations seems to be to reduce the width of that plume. The question is, if the car is doing a similar amount of work on the airstream will the new cars drag a narrower plume at a higher relative speed?

If so the following car will get a bigger tow in a straight line but might experience a larger variation in performance as it crosses the wake plume?

One further item on the racing lines issues is rubbering in and marbles. At the beginning of races drivers can challenge on many different lines but by the end of the race there is just one line in most corners. We saw this with Hamilton vs Verstappen at COTA. A solution would be much harder tyres, which would have the consequence of making Friday practise sessions unnecessary.

[jjn9128]

As I understand it the current cars, with their outwash concept, the cars drag a plume considerably wider than the car width. An objective of the new regulations seems to be to reduce the width of that plume. The question is, if the car is doing a similar amount of work on the airstream will the new cars drag a narrower plume at a higher relative speed?

If so the following car will get a bigger tow in a straight line but might experience a larger variation in performance as it crosses the wake plume?

Interesting question... if the drag of the car is the same then the change in mass flow is the same, just in a narrower area. So reducing the width of the wake would concentrate the effect of the wake towards the centreline. That is assuming drag is the same between 2018 and 2019. I think the loss of the cascades and r-vanes will reduce drag a bit next year, I'm sure there are other variants which will have an effect.

[illario]

Im aware that this is not related to topic. If memory dosent lie to me, there was a thread that disscused the relation and the inspiration from natyre to aerodynamics, but i didnt know how to find it. I will post it here without the intention of not respecting the topic on this thread.
https://www.nytimes.com/2018/10/23/scie ... seeds.html

Edit: "Drifting Dandelion Seeds Produce a Vortex Never Before Seen
The air flowing through the bristly tufts of dandelion seeds creates a vortex scientists had never viewed in nature."

[F1NAC]

Apparently teams reached early 2018 DF levels with 2019 regulations in their sims. From RB they've said that it won't do any better.

https://twitter.com/tgruener/status/1060125987587981312