I've seen this curled up splitter at several imsa events, (well, on tv that is) and I can't for the life of me understand how an uplifted splitter is working to provide downforce: maybe it's an optical illusion but it sure seems to me to be almost as if they ran into a solid object before taking to the track.
A splitter does what its name suggests - it splits the airflow. How it benefits the rest of the aero package depends on the entire aero package - it's not really about generating downforce in itself.
I imagined it would, and then the diffuser would suck it to the back. Though I'm not an aerodynamics expert.
Not sure, but would it be that the air has to travel further underneath, so goes faster and creates a low pressure zone which then pulls the car downward? Not an aero guy so just guessing. The wing on the back has a similar leading edge in the photo you've shown.
The splitter forces more air into the tunnel. Its not a very tall tunnel like GTP cars once had, but tall enough to add 10% of the car's weight in downforce. The tunnel contour roof drops down a bit compressing the air - that section actually creates a little lift while it accelerates the air flow at a higher pressure - lift.. Once past the front suspension the roof of the tunnel begins to rise and the faster airflow drops pressure across probably 3/4 of the tunnel length. Given the area of the mostly horizontal portion of the tunnel it doesn't take much of a pressure difference to have a notable effect.
This is an anti stall type of splitter. It allows the car to touch the ground (in corners for example) with side part and still not stall the air in splirter. It really looks a bit drastic but works just fine. And this "lip" just allows more air to go underneath the car then it enters the actual "splitter" with Venturi effect and all that stuff going on.
Looks almost as wierd as the old superspeedway wing on champcars that was angled up to increase drag and reduce downforce.. I never ceased to be amazed at how a simple lift device can be messed with by those college kids and their laptops....