Aircraft Community Noise Propagation Using Gaussian Beam Tracing with Moving Sources

An aircraft community noise propagation framework, MANIA-H, has been developed to enable efficient and accurate prediction of time-varying noise in realistic urban environments. The framework is based on the Gaussian Beam Tracing (GBT) method, which accounts for multiple reflections from complex urban structures and refractions caused by spatial variations in sound speed and wind velocity. To incorporate the effects of moving noise sources, a source-time-dominant method is adopted, in which the wavefield is constructed by emitting beams at discrete source times and evaluating their cumulative effects at observer times. As part of this formulation, a time-varying source time function with a Gaussian envelope is employed to model the temporal characteristics of the source and to account for Doppler shifts and beam travel time delays. To address beam truncation errors, caused by early termination of beams at reflection interfaces, a Virtual Beam Extending (VBE) method is proposed, which extends beam paths based on beam width and angle of incidence. The MANIA-H framework is validated through comparisons with time-history sound pressure level data obtained from flight experiments of a conventional helicopter. Finally, a case of noise propagation in downtown New York City is presented, demonstrating its capability for urban noise prediction with practical computational cost.