Correlating tactical jet noise characteristics with community annoyance

ABSTRACT:The proposed effort will begin connecting military jet noise source and field properties with waveform and spectral features that correlate with human perception and annoyance. Tactical military aircraft noise evokes significant community response relative to ordinary transportation noise because of its high amplitudes and unique features, such as significant shock content and low-frequency rumble. During Phase I, metrics will be examined for ability to correlate physical noise characteristics, such as source distribution, radiation properties, directivity, and shock content, with human annoyance and disturbance. A comprehensive evaluation of existing tactical jet noise measurement databases will be conducted to determine their suitability for Phase-II listener studies based on candidate metrics. The listener test experimental design, training protocols, and reviews will be completed. Experimental design for any additional required acoustical measurements will also be developed. To guide source characterization efforts and improve ability to extract significant noise features, a cost/benefit analysis of acoustical holography and beamforming will be conducted with full-scale data. These technical tasks will lay the foundation for quantifying source and field features that impact human perception in Phase II. The results will improve prediction of community noise impacts and guide future noise models, data collection, and noise mitigation efforts.BENEFIT:The teams combined experience in the areas of aircraft noise measurements, noise model development, and environmental impact determination associated with operations of military aircraft demonstrate a unique ability to assess the market need for this research and its utility and benefits to the community at large. In addition to a continuous effort to publish new and relevant research, active participation in multiple conferences each year, and numerous connections to both government and commercial clients provide us with the ability to increase awareness of this technology and market through a multitude of avenues. With the beddown of the next-generation of fighter jets such as the F 35, the demand for improved metrics that correlate jet noise exposure to human response and the desire for increased understanding of jet noise source characterization is only expected to increase,. The specialized jet noise metrics developed under this effort will attempt to represent the psychoacoustic response to high-power jet noise, which will improve in the evaluation of community impacts. Evaluating potential environmental impacts, including noise, is required by the National Environmental Protection Act (NEPA) for proposed actions, such as the beddown of the F-35. The environmental impact from aircraft are currently evaluated by the DOD, FAA, and other federal agencies using models such as NOISEMAP and AEDT, which output traditional noise metrics. Through the development of these specialized metrics, identification of the temporal and spectral jet noise characteristics associated with human response will inform requirements to improve and refine the sound propagation models used to evaluate community impacts. These advancements will lead to a deeper understanding of the community responds to jet noise and will improve the overall environment assessment of community noise exposures from tactical jet operations. These improved tools will translate into better relationships between the airfield and neighboring communities. Additionally, these specialized metrics are anticipated to play a crucial role in rocket noise impact evaluation from the emerging spaceport industry, regulated by FAA/AST, NASA, and the Air Force. Improved jet noise source characterization and a deeper understanding of jet noise generation mechanisms will inform future aircraft noise measurements. A high-fidelity representation of the noise sources will provide better inputs to environmental noise models, mission planning tools, and research tools than currently available. The acoustic source definitions, refined under this effort, will be used to improve predictions of ground personnel noise exposure, evaluate the performance of proposed noise control devices, and provide model refinement and benchmarking.