Ferrari SF24: new diffuser to gain driving stability, but less downforce than Red Bull and McLaren. Ferrari: the total downforce level remains lower than Red Bull and McLaren.

Scuderia Ferrari is competing for the F1 Constructors’ Championship in the current season. It is second in the standings, 36 points behind McLaren ahead of the Las Vegas Grand Prix, while being pressed by Red Bull, which is not giving up. Making predictions in this regard is particularly challenging. The Woking team remains the favorite, as it is ahead and has the best technical project. However, the Prancing Horse is fully determined to keep pushing, as recent changes made to the car have significantly improved the performance of the SF-24. A single-seater that seems capable of competing on equal terms against the McLaren MCL38 of Lando Norris and Oscar Piastri.

Great credit goes to the Maranello team for being able to react to the difficulties that arose following the aerodynamic updates introduced at the Circuit de Catalunya in Barcelona. This refers to the floor introduced in the Spanish Grand Prix last May, which stemmed from a misleading assessment by the technical department, then led by former Ferrari technical director Enrico Cardile. This self-inflicted move severely limited the performance of the single-seaters, causing serious difficulties for about three months. Fortunately, following the departure of Italian aerodynamicist Enrico Cardile, who moved to work on Aston Martin’s project alongside Adrian Newey, Ferrari managed to brilliantly correct the car, and the results have radically changed.

To the surprise of its F1 rivals, Ferrari has prominently returned to the top of the category. Three victories in the last six races and numerous useful placements. Two months in which the two SF-24 cars could have achieved even more without certain errors. Three races and a Sprint Race remain to fuel a dream in this final part of the 2024 Formula 1 season. Much will also depend on McLaren, as catching and surpassing them in the standings seems quite complicated without some “help” from their British colleagues, especially considering that Max Verstappen is highly reinvigorated and ready to fight for victory with his RB20.

From a technical standpoint, Ferrari has made a fix. Let’s proceed in order, though. In recent years, the Maranello team has introduced significant developments for the diffuser and keel design. We also know that since last season, they have worked extensively in this area of the car, and as previously mentioned, it is no secret that since the Spanish Grand Prix, the “Prancing Horse” has lost much of its floor stability. The new and different diffuser philosophy has caused significant challenges for Ferrari’s aerodynamics department, leading them down a path that ultimately proved to be highly flawed.

For this reason, the Italian team has chosen to take a step back. A well-defined central slide has been introduced on the SF-24. Within the width of the diffuser, surfaces must be created that comply with various points of the F1 regulations. There are a lot of things to respect, but with this generation of single-seaters, there is considerable design freedom. The transition area between the Venturi channels and the diffuser is quite delicate. The speed and pressure field undergo various changes at this point, so it is clear that issues of instability in the fluid flow can arise.

Essentially, by creating a specific central slide, the aim is to generate an up-wash effect that can provide a significant amount of localized downforce. In the solution adopted in Spain, the radii connecting the keel to the diffuser’s slide were quite small. In fact, observing the connection between the keel’s lateral surface and its rear area revealed a fairly sharp angle. Overall, the keel’s terminal zone had a very aggressive design, resulting in the generation of various vortices in that area.

These vortex structures serve to accelerate the flow and essentially reduce pressure in that area of the car. They are also useful for delaying the separation of the fluid flow from the wall, even though these structures are more sensitive to ground clearance. It is a concept not easy to explain. To clarify, one can imagine that the rotational flow has a certain structure, which “breaks” when the car lowers, and the wall-to-ground distance becomes critical. This, in short, is the origin of the bouncing phenomenon that has plagued the SF-24 cars.

In the version introduced at Monza, the central connection of the keel is designed to eliminate any kind of vertical step in the center. This is a useful move to ensure more stable downforce regardless of the car’s ground clearance, a crucial feature for maintaining aerodynamic predictability. The flow structure is less rotational. By this, we mean that vortex generation is still present. On current floors, we find a couple of characteristic vortices flowing through the car’s two main channels.

However, locally, the fluid structure is less vortical. Another distinctive feature of the new design is the transitions between the tunnels and the keel, which are characterized by larger curvature radii and a slight lowering of the local height toward the center. We see that the keel’s lateral surfaces continue until they meet and form a distinct segment, clearly visible in various images from the paddock. The new approach reduces these risks and aims for greater aerodynamic reliability, which is quite necessary for better managing the downforce.

Within this context, however, an important consideration must be made regarding the absolute value of the downforce produced by the specific configuration adopted by Ferrari. Although the work carried out by the historic Italian team to “fix” the floor has been effective, we must nevertheless acknowledge that this approach has reduced the capacity to generate absolute downforce. The total downforce level remains lower than Red Bull and McLaren, which are a step ahead in terms of fluid stability and the ability to implement various additional vortex-generating structures, whose management is highly complex.

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