Williams' low downforce rear wing
Williams designed a new one-off low downforce rear wing for the Canadian GP, which unfortunately for the team didn't pay off. In fact the special rear wing did not offer a big top speed improvement, at least not compared to what other teams came up with. During qualifying for instance - which is of course always with DRS open at the speed trap, the drivers posted 318.8 and 317.8 km/h, good for 19th and 20th positions on the top speed rankings.
Interesting as well is how this is a competely different rear wing to Williams' unraced 2011 Canada spec wing. Last year, the team opted for a design with raised outer edges, while this year's wing obviously features a raised central part.
The concept is not totally new, similar wings, though rather W shaped, as Renault first did in 2010.
I would suppose that prime reason for such design would be that the center section of the wing will retain lower pressure, and such effect would cause subsequent lower pressure levels at the wing tips, meaning less vortex as well.
Generally, the wing tip vortex will have low pressure core, but their overall strength is resultant of pressure differential between upper and lower wing surface, so reducing it in one side of the equation would mean less wing tip vortex, too.
That's my humble aero guess, we haven't seen whether this had the desired effect, but the wing was raced anyway.