Exhaust-blown diffusers are to be eradicated from Formula 1, with off-throttle blowing banned from the British Grand Prix in a couple of weeks' time, and a reversion to periscope-style exhaust outlets required in 2012.
Is there, however, another means of achieving some vestige of the same effect? Well, those who prefer vertical bathing might be aware of something dubbed the 'shower curtain effect'. This is the tendency of a flexible curtain to be tugged inward by the downward spray of water ejected from a shower-head. One theory holds that the falling water drags the surrounding air down with it, and this airflow creates low pressure within the shower cubicle, pulling the curtain inwards; another theory argues that the spray creates a vortex, and it is the low pressure within the centre of the vortex which explains the inward force acting on the curtain.
So, can this effect be used to any advantage in Formula 1? Well, how about using the cooling circuit pump for the sidepod water radiators to spray water into the outer part of the diffuser, the same area into which the exhaust flow is currently directed? One could reasonably argue that the primary purpose of the pump is to cool the water circulating around the engine, and any aerodynamic effect is merely a by-product.
One would quickly run out of water, of course, and it would be difficult to justify the weight of an extra water tank capable of blowing the diffuser over a race distance, so perhaps this is an idea for qualifying use only. However, consider Grands Prix such as Malaysia and Singapore, where Formula 1 races in humid environmental conditions. How about incorporating a condenser into the sidepods, which takes the ambient water vapour, condenses it, and then sprays it into a duct at the outer edge of the sidepods?
When you do the sums, of course, the benefit of spraying water into the diffuser airflow might well be negligible, and one might also query how long such a concept might survive before being banned. It's just a thought, though...