Airflow rates by combined natural ventilation with opposing wind—unambiguous solutions for practical use

Analysis of possible airflow rates by combined natural ventilation with opposing wind in rooms with two openings shows multiple solutions, instability and hysteresis. In this paper, it is analysed to what extent these phenomena should be considered under practical conditions. The analysis shows that unambiguous solutions can be obtained if difference between indoor and outdoor temperature is known at start, i.e. when heat sources are switched on and ventilation openings are opened. Discontinuities in airflow rates occur under certain specific conditions.