The weather at Spa-Francorchamps has always been uncertain. Even this year, the weather conditions underwent continuous changes, going from intense rain on Friday to sunshine on Sunday. This has certainly increased the spectacle of the cars passing through, but it has also allowed for the observation of very interesting details. In fact, in these conditions, the air currents that impact the cars become very evident. Let’s explore together, in a sort of open-air wind tunnel, the path that the air takes in flow analysis.
The Brackley car arrived at Spa-Francorchamps with innovations in the rear part of the sidepods. This new specification has certainly affected the flows that interact with the German side’s car. Looking at our correspondent’s photo, we can notice that a cone is generated behind the front wheels, expanding towards the rear. Moreover, this cone is very distinct, a sign that the flows displacing the water are closely packed in their expansion. These flows then continue towards the rear and largely shield the wheels, which act as a significant aerodynamic block. Besides sealing the underfloor to prevent porpoising, these flows create a sort of suction effect on the tires. This happens because the flow lines we see carry high energy and create a low-pressure zone in front of the wheels, reducing their drag.
Even on the Prancing Horse car, the flows are evident, although less pronounced compared to those seen on the W14. This difference could stem from a different management of the flows, which in this case might require less energy to perform their function. It’s interesting to observe a small upward flow of air directed above the rear wheels. This element doesn’t seem to be part of the underlying vortices but could be generated by another component. Of course, we don’t know for sure if this is indeed the case or if it’s just a perspective trick. Returning to analyze the lower part of the car, it’s clear that these flows expand and cover the 405 mm of the rear tire’s tread. Just like on the W14, covering this area significantly reduces tire resistance.
The flow analysis has also allowed the visualization of the water wake that the cars generate at high speeds. What emerges is that reducing this effect will likely be challenging unless the technical parameters of the diffuser are modified, as it is the main culprit behind this “wall” of water.