Looking back at new diffuser photos made me think again about the new keel design and some peculiarities. Ferrari first introduced full rear boat keel design on 2nd F1-75 floor, introduced in Spain. It was a clean design and fully following the shape of vertical surfaces until they meet in the middle, as you'd expect from a such a geometric shape.
While new keel, more than 2 years later, looks like this. 2nd photo is old keel design and I was convinced central mini ramp was a leftover geometry to be able to use "old" diffuser to save costs. As closer carbon weave and geometry inspection shows, new floor is completely new in that area and the geomwtry is similar, but not the same at any vertical cross section
This mini ramp can be explained by existing chassis (crash structure) and gearbox design and thus it has to exist. Or it's there for aero purposes. Either way, I think there is some downforce generation on its bottom surface, ie the ramp. The air coming on either side follows the angle of main tunnel diffuser roof and this angle of airflow gradually reduces going down. In any case, airflow won't be anywhere near paralel to the central ramp once it reaches it, so one of two things happen:
- two contra rotating mini vortices are shed on each side (if the transition radius is small enough)
- there is an accelerarion of air on the transition radius if no vortices are shed
Both phenomena mean some downforce generation, where vortices would probably generate more, but I'm not sure if they can be formed. Available photos make it impossible to estimate if transition radius from vertical ramp wall to ramp surface is small enough. In any case, there is a discrete central keel junction at the bottom, thus eliminating any vertical kick, so any downforce generated there is practically very stable regardless of ride height at any time.
Another interesting thing are these large radii transitions between floor tunnel roofs and keel, circled on each side above. There is a subtle drop in local roof height towards the keel, in an area where the main horizontal tunnel roof is already following near-mandated diffuser ramp geometry. I think this is where Ferrari is making up for lost keel ramp vertical kicks (present since launch spec floor), which generated a bit of rear local load but very dependant on ride height and probably subject to stalling in very low ride heights. As we all learned, this is one of the things that trigger bouncing if the stalled surface is big enough.
Both of these features make a big evolution step of diffuser area and Ferrari have done a lot of changes there in these 3 seasons. Seems to me like they don't want to generate any downforce with vertical kicks anywhere any more and want to rely on tunnels to generate the bulk of the floor downforce. This latest evolution opens up a lot of room for improvement in my view, especially with an eye of 2025 car.
