Assessment of boundary‐layer characteristics on building façades under variable wind regimes in urban environments

This study focuses on investigating the spatial characteristics of the air boundary layer on building façade surfaces, a crucial factor governing heat and mass transfer and energy efficiency. The goal was to obtain a system of approximation functions describing the boundary‐layer thickness as a function of height, wind speed, and flow impingement angle. The methodology involved numerical simulation of the static pressure distribution and boundary‐layer thickness on the surfaces of a typical Ukrainian residential building of the I‐464‐3 series. Based on a multifactorial data analysis, an approach was applied to select the optimal functional dependency from five analytical forms (linear, power, hyperbolic, logarithmic, exponential) by minimizing the root‐mean‐square deviation. The results show that increasing the wind speed from 2 m/s to 5 m/s reduces the mean boundary‐layer thickness but significantly increases its instability and scatter (up to 0.2 m–0.3 m in rear zones), which is confirmed by an increased coefficient of variation. The novelty lies in the systematic acquisition and analysis of approximation dependencies for all surfaces of a typical building, and the physical interpretation of anomalous negative thickness values as markers of local flow separation and recirculation zones. The practical significance of the results is their applicability in improving the accuracy of thermotechnical and aerodynamic calculations for façade systems and assessing wind loads in urban development.