In this, PowerTec 10, episode 34, part 2 of rule #1, DV covers the importance of the bowl shape as this can utilize the kinetic energy in the main part of the port to step up the pressure at the approach to the valve seat.
Just as a matter of reference here this is about the most comprehensive porting info on YouTube and it will, from the tech aspect, take a novice right through to expert over the course of the 5 rule series. If you don't think we are going in that direction we would be happy to hear you comments concerning such.