Alfa Romeo had a productive pre-season test, with good mileage on all three days, including two full race simulations. The team also introduced some aerodynamic updates to the C41 during the test, attempting to extract some more performance ahead to the first race of the season. Starting with the front wing, the tips of the upper two elements were trimmed outboard.
This may be designed to move the Y250 vortex further outboard (once it has rolled up into a single vortex) to improve downstream performance (e.g. from the bargeboards). The third element loses support due to the lack of elements behind it, so it is important to ensure that its flow health is retained, otherwise there will be greater losses pulled into the Y250 vortex core. On both of these wing options, the footplate channel featured a slot, not present when the car underwent a shakedown in Barcelona.
In areas of the aero map where the front ride height is low and roll is high, the outboard part of the front wing (one one side) becomes very loaded, as do the vortical structures shed from the strakes, footplate etc. Even though Alfa Romeo has a more inboard-loaded wing, the elements are very close to the ground outboard, so this effect will still be important. Adding a slot in the channel will enable some high energy, clean flow on to the suction side of the wing, improving the losses in the core of these structures.
Further back, on the bargeboards, two changes have been made. Firstly, one of the mini-bargeboards now features a slot at its tip. The vortices off these elements can become very loaded and carry significant losses in certain parts of the aero map, which can be alleviated by splitting the tip into two and altering the vortex roll-up process. Lowering the losses then improves the energy of the onset flow for other downstream components.
At the back of the bargeboard, the trailing edge has been chamfered, removing overall area. This part of the bargeboard is drag-inducing due to its orientation to the centreline of the car, so this new design may better optimise the downforce/drag trade-off. Finally, at the rear of the car, Alfa Romeo have introduced a new rear wing endplate. It features a leading edge element, which is disconnected from the endplate at its base. This should help keep flow attached to the inside of the endplate under high yaw, and also increase the mass flow between the endplates, raising the load of the wing.
In tandem with this, the number of vertical elements on the endplate has been reduced by one to four, and their span has been lowered accordingly (see below). This could well be a change made for structural reasons, as it is important to keep enough continuous endplate width to carry load down to the connection on top of the diffuser, and this width has been reduced with the leading edge device.
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