Natural ventilation from dynamic city winds

Natural ventilation is a bioclimate strategy for maintaining thermal comfort and air quality in buildings. Increasingly large cities, along with climate change, have exacerbated the effect of urban heat islands and pollution, raising public health concerns.

Optimizing natural ventilation design begins with an understanding of how building microenvironments shape airflow and particle dispersion. Wind patterns are dynamic, but current research on indoor airflow regulation has mostly based experimental assumptions on steady or averaged wind directions. Noting this research gap, Zhu et al. designed a novel dynamic wind direction meshing framework accounting for transient wind conditions.

Specifically, the authors integrated a dynamic rotating mesh into a large eddy simulation framework, enabling realistic predictions of wind direction changes in urban wind fields. Their results showed that even minor wind fluctuations exert a significant impact on ventilation efficiency — a 1° change in fluctuation amplitude led to a 13.13% reduction in tracer gas decay, indicating less effective pollution dispersion.

“The proposed regression model provides a valuable predictive tool for engineers, leading to more accurate urban wind field analyses,” said author Yuwei Dai. “In doing so, this work informs air quality control and sustainable city planning.”

By considering multi-aperture ventilation scenarios and incorporating multi-physics coupling mechanisms, the authors plan to improve their meshing framework’s generalizability to real-world scenarios.

“Future projects will extend the framework to dynamic wind vectors in urban cross-ventilation, integrating multi-physics mechanisms like thermal buoyancy for improved predictions,” said Dai. “Research may also explore wind-field interactions with urban morphology to develop generalized models for mesoscale weather applications, enhancing pollutant dispersion and airflow understanding.”

Source: “Rotating mesh framework and dynamic wind direction variability effects on building ventilation with Large Eddy Simulation,” by Haotian Zhu, Yuwei Dai, Chunxiao Su, Chanjuan Sun, Zhijun Zou, and Haidong Wang, Physics of Fluids (2025). The article can be accessed at https://doi.org/10.1063/5.0267647 .