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Description
Thin membranes exhibit a drum-like acoustic response when subjected to rainfall. The resulting rain-induced noise can have a substantial impact on acoustic comfort and may negatively influence communication quality, speech intelligibility, and cognitive task performance. Consequently, a detailed assessment of rain-induced noise characteristics on membrane structures in different architectural configurations is of considerable importance. Moreover, the inherent differences between natural and artificial precipitation -particularly in terms of droplet size distribution and terminal velocity- highlight the need for validation of artificial rain test scenarios against natural rainfall conditions.This study presents a comparative investigation of acoustic responses generated by natural rainfall and by controlled single-droplet impacts performed in a semi-anechoic chamber on Ethylene Tetrafluoroethylene (ETFE) membranes. Although theoretical and numerical models are available to describe the acoustic response of individual droplet impacts, it remains necessary to evaluate the extent to which a superposition of such events- designed to replicate the size and velocity distribution of natural rainfall- can adequately represent real rain conditions. In this framework, in the here presented work, theoretical droplet-impact modelling was employed to support the interpretation and validation of the experimental results.The analysis was further extended to two structural configurations: a single-layer ETFE membrane and a three-layer ETFE cushion system. The outcomes of this study are expected to contribute to improved simulation strategies for natural rain noise and to support more reliable subjective and objective assessments of rain-induced acoustic environments in architectural spaces.