Investigation of the Impact of Real Atmospheric Conditions on Noise Propagation from Small Aircraft Technologies

Abstract

The commercialization of urban air mobility (UAM) is increasingly coming into focus. Their range of operation is often limited by noise restrictions in urban areas. Besides psychoacoustic factors, the noise perception of individual flights on the ground is strongly affected by sound propagation through the atmosphere. Recent work has focused on scenario predictions of ground-perceived noise originating from large aircraft. Current prediction models use standardized atmospheric conditions to calculate sound propagation. Previous research shows that at high flyover altitudes and scenario calculations, neglecting meteorological factors gives accurate results for the noise perception on the ground. However, a single small aircraft flies at low altitudes such that assumptions as the strong damping of high-frequency noise propagating from an aircraft to an observer are no longer applicable. Therefore, this study quantifies the differences between standard atmospheric conditions in comparison to real atmospheric relations for low flyover altitudes. The impact of several meteorological state variables is investigated. The atmospheric sound propagation is performed by a numerical Lagrangian sound particle model comparable to ray tracing. The analysis highlights the limitations of current modeling approaches. Future work could suggest optimizing flight paths for local weather conditions to minimize