Porpoising the new enemy for 22 Regs F1 cars

[John S]

Alfa Romeo and Haas both had very limited running yesterday, both due to the very same issue - Porpoising!   
Every single team is also experiencing the same issue to different degrees, but what is it and how can it be solved?
Maybe FIA banned mass dampers too soon. 
Grandprix247.com offers some insight:-

What is porpoising?
Porpoising can be a common issue with ground effect cars, particularly those that are producing higher amounts of downforce.

On a ground effect car, as the speed of the car and the downforce created increases the car is essentially “sucked” further towards the track surface. However, as the ride height of the car decreases there is a point reached where flow separation in the diffuser tunnel throat occurs that causes downforce to be reduced.

This loss in pressure results in the ride height then increasing and downforce is again regained, and the ride height reduces again and the whole process repeats over and over at reasonable frequency. This ‘bouncing” is known as porpoising.

Why is porpoising a problem?
Particularly at the end of a high speed straight this characteristic can not only cause potentially catastrophic floor damage, but also chassis instability, affect the cars braking ability, and it can also impair the drivers vision due to the vibration.

The reality of Wednesdays first day of F1 testing was that apparently every team was having to deal with this issue at some stage and many floor changes were performed due to the damage caused by it. In the previously mentioned examples of Alfa Romeo and Haas, the issue was so severe that test run plans were compromised.

What are the solutions to porpoising?
Interestingly, most teams are reporting that porpoising is mitigated to some degree when DRS is open, which sort of makes sense when you think about it because when it is open downforce is reduced and the ride height at the rear raises in response.

There are mechanical means to help with reducing the severity of porpoising, such as stiffer springs and tuning of dampers. One of the better options available to the teams might have been the mass damper, or “inerter” as they have become more commonly known, but alas as of the end of 2021 their use has been banned in F1.

Alleviating the issue altogether however would certainly require some form of aerodynamic solution, such as a vortex generator that cleans up the boundary layer separation at the point at which it is occurring.

It is intriguing that on the very first day of track F1 testing of a completely new set of aero regulations that every team experienced the very same issue, and so it would hardly be surprising if the flow separation is in the same area for every team.

Accordingly, it may very well be that a minor concession to the new 2022 regulations is made swiftly allowing the inclusion of a currently banned vortex generator mitigating this issue.

(above excerts Courtesy Mark Kay, grandprix247.com, Today.)

[Jericoke]

Interesting.  In the past, cars that generate the most down force had the advantage.  Now it seems that cars generating too much downforce have a problem.

[John S]

Great example of porpoising on track in Barcelona from LeClerc in the Ferrari.

https://twitter.com/i/status/1496888665431326726

[Willy]

What did the mass dampers do that caused them to be banned. Other then deal with porpoising?

[Andy B]

GR stated that the Mercs have not had this issue.

[John S]

GR stated that the Mercs have not had this issue.

Well it seems he changed his mind, in an article on GPfans.com, this evening.

On how bad the 'porpoising' was for Mercedes, Russell added: "We didn't experience it too much between one thing and the other, but it is not too pleasant at all.

Think George gave an earlier interview as director of GP drivers association in which he needed to confront the safety issues around porpoising at the test. Seems he sought to downplay/deny any Merc problem, as any new recruit might when trying not to embarrass his team - ah bless. 

https://www.gpfans.com/en/f1-news/76482/russell-suggests-new-car-porpoising-a-safety-concern/

Whilst GPblog.com has no doubt that Merc have problems along with most others.

https://www.gpblog.com/en/news/105079/mercedes-wrestling-with-porpoising-issues-during-2022-f1-winter-test.html

[lkjohnson1950]

What did the mass dampers do that caused them to be banned. Other then deal with porpoising?

They were ruled to be a movable aerodynamic device because they stabilized the car allowing the aero to maintain full function.

[John S]

Here's a vid to explain a bit about porpoising. WTF1 also seems to confirm Merc in as much trouble as rest on this issue.

[Jericoke]

Apparently this was an issue in the previous 'ground effects era'.

I don't know if they solved it then, but never wrote it down?  Or modern engineers didn't even bother to look at the old notes?

I think the funny part is that the wind tunnels are so expensive and fragile, they can't afford to let the model cars bottom out, making it impossible to detect/test porpoising in the wind tunnel.  Looks like the wind tunnel 'advantage' for the slower teams won't help at all, and in fact may just provide bad data.

[cosworth151]

It sounds like raising the rear ride height might help.

[John S]

It sounds like raising the rear ride height might help.

Yeah that'd do it Cos, but you'd lose a fair bit of speed that way on other parts of the track. - Now would you lose more than you gain on the straights?
Reckon that's the tricky conundrum all the teams have to wrestle with.

[jimclark]

Apparently this was an issue in the previous 'ground effects era'.

I don't know if they solved it then, but never wrote it down?  Or modern engineers didn't even bother to look at the old notes?

Not apparently.....absolutely. Yes it was solved.

I'm also curious (quite surprised 'matter of fact...) as to what's different now to make it rear it's ugly head  once again, 40ish years on. 

[jimclark]

"I remember in the old days of F1, the ground-effect Ligier (pictured above in Argentina in 1979) going past the pits at Monza porpoising so badly that the front tyres were coming off the ground by a good two inches!?"
https://the-race.com/formula-1/gary-anderson-the-old-ground-effect-obstacle-facing-f1-teams/

See my signature. vvv   

[John S]

Seems Ligier had issues all season in 1979 with ground effect.
 
Heres's a quote from the comments section on The-race.com by Rod Callaghan Art Services:-
"I recall at Zandvoort in 1979 the Ligier team we’re generating so much downforce they had some new springs made up overnight to try to keep the cars gluing themselves to the road and then letting go.
The new springs were 4000lb/inch, which is almost beyond comprehension.
This is the scale of magnitude engineers are looking at."

Heck thats some stiff springs.     

[jimclark]

About what they're running these days, no? (yes, a slight exaggeration....I think).

I lament the days when suspension travel was required..........not running on mandated glassy smooth "billiard tables" of today......