Revisiting Internal Pressure Dynamics in a Single Opening Enclosure Ventilated by Wind

This paper describes a re-analysis of internal pressure and building ventilation in a single-opening enclosure ventilated by winds. The dynamics of internal pressure is governed by a nonlinear oscillation equation. An alternative semi-nonlinear approach is proposed for obtaining the amplitude and phase shift of the periodic motion, the resonant frequency and resonant amplitude. Our new approach reproduced two of the commonly used existing linearization results. We also obtained explicit formulas for both the amplitude and phase shift of the internal pressure, as well as the airflow velocity through the opening. Numerical "accurate" solutions of the original governing equation were also obtained to evaluate our theoretical ones. We also found a quasi-periodic motion exists in addition to the periodic motion already found in the literature, but this has not been proved in any physical experiments.