Large Eddy Simulation of Cross an‎d Parallel Natural Ventilation with Wind Direction for Different Window Configurations

10/18/2025 12:00:00 AM

Natural ventilation, as one of the sustainable an‎d low-energy approaches for providing fresh airflow in indoor spaces, has recently attracted significant attention among researchers. In this study, the effect of window type an‎d configuration on the performance of natural ventilation in an isolated building subjected to incoming wind flow is investigated. Four window configurations are considered: Case 1 (empty opening with wind perpendicular to the windows) as the reference case, Case 2 (empty opening with wind parallel to the windows), an‎d two additional cases including a Casement window with vertical hinge an‎d a Pivot window with horizontal hinge. The Large Eddy Simulation (LES) approach is employed to analyze airflow structures an‎d pollutant dilution processes. With its ability to reproduce turbulent fluctuations, LES enables a detailed examination of flow dynamics, vortex patterns, an‎d pollutant removal. The results show that the reference case, with openings perpendicular to the wind direction, provides the best performance due to the formation of stable cross ventilation, which enhances turbulence, promotes mixing, an‎d reduces pollutant concentration. Among the parallel configurations, the Casement window with vertical hinge strengthens turbulent kinetic energy, improves air mixing, an‎d thereby reduces pollutant concentration more effectively than the other parallel cases. From a quantitative perspective, the normalized air change rate (ACH) is obtained as 1.00 for the reference case, 0.76 for the parallel simple opening, 0.87 for the Casement window, an‎d only 0.18 for the Pivot window. Thus, among the parallel configurations, the Casement window achieves the highest performance, approaching that of the reference case. Overall, the combination of qualitative an‎d quantitative results indicates that the type an‎d opening direction of windows play a decisive role in the performance of natural ventilation; proper selec‎tion of window configurations can enhance indoor air quality an‎d reduce energy consumption in buildings.

تهويه طبيعي

Natural ventilation

Reza Bahaadini

Farzad Bazdidi Tehrani