Just out of curiosity Chad, are air velocity and flow not directly related? Wondering why one would focus more on the air velocity. I'm just trying to learn.
The velocity of air moving through the port is primarily a function of how much air it is moving vs. the port's volume (more accurately, its cross-sectional area). As the port moves more air, the velocity goes up; eventually getting so fast it blows the shortside turn and separates. When that happens, the port will typically stall, flowing no more or even less air no matter how much further the valve is opened. How much air will get through before the shortside separates and the port stalls will depend on the shape of this critical part of the port. The shortside form is a key limitation on the ultimate flow potential of a head. All ports aren't created equal, and some have a decent shortside form while others are handicapped in this area.
