Assuming you mean these:
Rather than these which is what comes to my mind with Venetian blind and F1:
If so, the vertical flaps at the edge of the sidepod help to increase circulation of the bargeboard area - which increases downwash and outwash at the front edge of the floor. It also increases downforce at the outboard front edge of the floor (the "hammer head"). The shaping of the flaps then helps to reduce the induced drag but then also shift the wake of the flap so it isn't re-ingested by the floor.