1. Air density is going up from air being compressed.
2. Mass flow rate is also going up because you're pumping more air mass through the system with the turbo or supercharger.
Were measuring cfm but ok mass flow rate, M = r x v x a right ?
So and NA engines Air density varies but say it's static for a moment at atmosphere psi 14.7 & we add a turbo and double it to 29.4 psi overall so the density is twice that of an NA engine so per cubic foot it's got about twice the oxygen and fuel molecules why makes about double the power.
So density is r in the formula so in the turbo r would be twice the amount than in an NA engine in this example so doubling the density would double the mass flow rate with Velocity and Area still being the same turbo vs boosted, NA 100r x 1v x 1a = 100m, Boosted 200r x 1v x 1a = 200m.
Neither of these things are constants in real life so bear that in mind. Also.... very importantly.... remember that at the flow rates in real life, vs on a Flow bench, are much higher and therefore velocities are going to be higher. The flows are going to be much more chaotic (non laminar). And there's a bunch of pressure waves all around in there. The formulas are useful for gaining insight and understanding but they aren't always good predictors.
I totally agree, the velocity in the engine probably way higher and same with overall air flow, but we see some correlations between the bench and what works in the engine.