This is very interesting stuff. Look at the images labelled "velocity slice at ground plane" and "on the top side of the floor". You can clearly see the "Y250 V

This is very interesting stuff. Look at the images labelled "velocity slice at ground plane" and "on the top side of the floor". You can clearly see the "Y250 Vortex" going between the front wheels and out around the barge boards. This vortex structure exists because the front wing main plane needs to be flat for +/- 250mm at on the Y axis from the center line. In order to get the outwash to the barge boards and around the rear wheels, the front wing needs to generate a huge vortex right where the wing starts. You can see the Y250 Vortex structure in this old footage from Mark Webber driving the RB9 in humid conditions where it forms a condensation trail as the air pressure drops: https://www.youtube.com/watch?v=ZlDnd3B1rhs https://www.youtube.com/watch?v=ZlDnd3B1rhs