"Particularly important since the majority of flow is at the centre of a pipe"
Only when you have laminar flow, in general air in a pipe or duct travels in a vortex, the air closer to the duct walls has a higher velocity, and lower static pressure while the air in the centre of the vortex is slower but has a higher static pressure. So, a higher MASS of air is delivered in the centre but the air at the extremes gets there quicker. The quicker air can increase power but it's the slower, high mass air that produces torque, and torque talks. Think blowing slowly on a camp fire to help the embers glow as opposed to quick bursts that extinguish the fire.
Interesting reading & the dynanmics of air in enclosed spaces has me intrigued. According to those documents, the butterfly throttle plate is still superior in a street engine & I’ll be exploring the mod soon.