A model of pressure--velocity admittance function for local pressures on building roofs and leeward façades

This study revisits aerodynamic admittance functions for roof pressures on buildings subjected to turbulent wind conditions. A new model for pressure–velocity admittance is proposed, expressed as a product of space- and frequency-dependent factors. Unlike classical approaches, the proposed formulation does not rely on the mean pressure coefficient and is therefore better suited to handle separated flow regions. The spatial dependency is linked to the local standard deviation of roof pressure, while the frequency-dependent factor varies slowly across the roof surface. Both factors can be readily identified from numerical or experimental data, as demonstrated in this paper, using state-of-the-art simulations of flow over a generic building. Two simulations with differing turbulence intensities in the incoming flow are analyzed. The proposed model accurately captures the pressure fluctuations on the roof and on the rear façade of the building. The observed slow spatial variation of the frequency-dependent factor suggests that this model provides a robust framework for physics-based classification and offers practical benefits for wind engineering design and codification.