Aerodynamic performance investigation of a wind-driven ventilator with vertical vanes under skew wind conditions

Wind-driven turbine ventilators with vertical vanes are extensively utilized in natural ventilation applications. Typically installed horizontally on rooftops, these ventilators have been assumed in previous studies to operate under perpendicular wind conditions. However, it is crucial to recognize that wind direction varies depending on climate, location and time. Previous research has overlooked the influence of wind direction and installation angles on ventilation performance. This study aims to experimentally investigate how wind direction affects wind-driven ventilators with vertical vanes. The findings suggest that flow fields with incident angles below 40° exhibit similar characteristics. As the incident angle increases, the ventilation rate does not decrease significantly and may even increase within a certain range of angles. When subjected to upward skew winds, the discharge coefficient typically falls below 1.0 and decreases as the incident angle rises. Conversely, when subjected to downward skew winds, the ventilator effectively prevents backflow. It is essential for the installation and operation of turbine ventilators to consider local wind conditions and installation sites comprehensively to optimize natural ventilation efficiency.