This model contains the empirical expression according to ASHRAE handbook.
It is also applied in EnergyPlus as the object ZoneVentilation:WindandStackOpenArea.
ASHRAE. (2009). 2009 ASHRAE handbook: Fundamentals (SI ed.). American Society of Heating, Refrigeration and Air-Conditioning Engineers.
U.S. Department of Energy. (2023). EnergyPlus Version 23.1.0 Documentation: Engineering Reference [Build: 87ed9199d4]. U.S. Department of Energy.