This model describes the one-directional pressure driven air flow through an opening based on user-provided tabular data describing the relation between mass flow rate and pressure difference over the component.
ṁ = f(Δp),
where ṁ is the volume flow rate and Δp is the pressure difference.
Based on the table input, a cubic hermite spline is constructed between all points except for the two last pairs of points. These point are connected linearly.
The constructed curve is the direct relation between ṁ and Δp.
A similar model is also used in the CONTAM software (Dols and Walton, 2015).