Red Bull revealed a fascinating upgrade to the RB8 in Barcelona this morning, which seems to have drawn upon the urban architecture of Milton Keynes for inspiration.
As first recommended by McCabism in October of last year, although F1 exhaust exits must now be angled slightly upwards, and placed 250mm above the reference plane, if those exits are made almost flush with the surface of downward-sweeping sidepods, then at high speed the downward cross-flow will pull the exhaust jet towards the diffuser.
Red Bull have now incorporated such a design, in conjunction with a sort of bridge, or ramp, which appears to direct the exhaust gases down towards the outer edges of the diffuser, (picture courtesy of a Twitter link from Jason@crucial_Xtreme).
Beneath the bridge is an underpass straight out of central Milton Keynes, which takes the air flowing along the sidepod undercut, and funnels it towards the coke-bottle, and thence over the central section of the diffuser, and through the starter-motor hole.
In effect, it's like a hydrodynamic version of the cross-over at Suzuka. It's a way of stopping these two flows from interfering with each other, now that the regulations have forced the exhaust exits to be further forward and further upwards. In retrospect, it's clear that the 'blister' which houses the exhaust exit on the new McLaren, was their response to the same problem, the overhang of the blister achieving a comparable separation of the two flows.
Perhaps we can attribute the inspiration for this to the overhang at the McLaren Technology Centre...