Study of Airflow in a Naturally Cross-ventilated House -Evaluation of Nat-ural Cross Ventilation Considering Flow Fluctuation by Using Large-eddySimulation (LES)

摘要

Cross ventilation in interior spaces is a commonly used natural ventilation method in Japan during moderate seasons, including summer. Clearly, cross ventilation is a complex phenomenon. In a previous study, a steady airflow distribution was studied over time for a simple house model with two windward and leeward openings on opposite walls, however, the wind direction and velocity outside the house was found to vary. Consequently, the airflow distribution varies depending on the outside wind direction and velocity. Moreover, the outside wind turbulence affects cross ventilation, for example, in the case of two wall openings symmetrical to the wind direction. Recently, unsteady fluid flow phenomena were analyzed using large-eddy simulation (LES). LES can simulate the time variation of a flow. In this study, airflow computation results for a cross-ventilated house are reported. Five cases of a simple house model were considered, and a natural cross-ventilation evaluation method, which considers flow fluctuations, is proposed.