Completely compatible with M
oon covers.
If you observe the spray spiraling out of truck's front wheelwells on the freeway in the rain, you can see the energy involved in the air circulating into and out of the wheelwell. Now, air doesn't get thrown out that far into the ambient flow because it doesn't have the mass; the wheel disk is swept by the ambient air flow. So I suspect the air curtain manages air the wheel disk doesn't see.
The dimensions are interesting, height and width, and it only covers the top third of the tire. I wonder if the roof of the air curtain slopes upward to the top of the wheelwell. Those raised ribs are vortex generators to maintain a coherent jet of air.