High pressure (outside the engine) to an area of low pressure (inside the intake and engine)....the pressure drop is due to in part the air being accelerated and hence lowering it pressure.
Here endeth my understanding of Mr Bernoulli's theory
Good description of the
suck part of the
suck, squeeze, bang and blow theory, now if only you could move on to the part about why do we also have a vortex
I think it has to do with velocity vectors and not just gross pressure gradients. So if you have two velocity vectors creating a shear component at the same time that you also have a gross pressure gradient, viola, you have a vortex. Now just add some visible water vapor and we have a photographers' dream
