Tech Bite: Sauber introduce a leading edge slat
Sauber didn't introduce many upgrades at the Spanish Grand Prix, but one small change to the C33 came in the form of a leading edge slat.
Sandwiched between the side of the cockpit and the outboard vortex generator, the horizontal winglet (see highlighted section) helps stabilise airflow over the sidepod.
Working in tandem with the aforementioned vortex generator the slat works the airflow as it moves over the sidepod. The idea is to increase the operating window of the sidepod, providing performance through a wider speed range.
Ordinarily as speed builds, the airflow passing over the sidepod creates a thicker boundary layer toward the surfaces rear-end. At a certain point that airflow will begin to separate/detach, increasing drag and creating an undesirable airflow structure that could impact the performance of other parts downstream.
The slat and vortex generator combination introduce vortices that reduce the boundary layer thickness, delaying separation, improving the overall performance of the sidepod.