Airborne Weapons Noise Prediction Model - 06/02/06

BRRC is working to characterize and model airborne weapons noise.

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Background

A number of aircraft and ground-based weapon system noise models have been developed over the past 30 years to estimate noise levels from military operations. The results of these models are used to assess the potential for community and environmental impacts from existing and proposed operations. Current Department of Defense (DoD) noise models use common aircraft and weapon system source noise databases maintained by the Air Force Research Laboratory, U.S. Army Construction Engineering Research Laboratory, and Naval Facilities Engineering Command. These models and the source noise databases do not provide the capability to assess noise impacts due to airborne weapon operations. A new computer model is needed that can model the combination of aircraft noise and elevated weapon noise that occur in air-gunnery operations. The complexity and computational labor involved in assessing noise impact from air-gunnery operations dictates the need for an efficient and flexible software tool.

Objective

The objectives of this project are to (1) characterize the noise generated by airborne weapon systems, (2) evaluate and refine current weapon noise propagation algorithms for airborne platforms, and (3) incorporate these refined algorithms and additional data requirements into the new noise model simulation (NMSim) being developed under the SERDP project Advanced Acoustic Models for Military Aircraft Noise Propagation and Impact Assessment (SI-1304). This integration will enable completely new sets of operational scenarios to be modeled, which will assist in public presentation and understanding of potential noise impacts and their mitigation.

Process/Technology Description

The overall process will consist of three main elements. The first will involve measurement of real, airborne weapon systems to characterize the noise data required for accurate modeling. The characterization of air-gunnery noise is complex because of the combination of various sources and aircraft platforms. Second, this complexity requires modification of weapon noise propagation algorithms. Modifications will involve three-dimensional representation of the noise sources to properly describe the air to ground propagation and to account for potential shielding/interference from the aircraft itself. The final step will involve the integration of the air gunnery data and algorithms into the current Advanced Acoustic Models for Military Aircraft Noise Propagation and Impact Assessment, which are being developed under SERDP project SI-1304. Once integrated, computer simulation can provide visualizations of the resultant dynamic noise field.

Expected Benefit

The information developed under this project will represent a significant advance in understanding the contribution of air-gunnery operations to the overall noise generated by range operations. This will allow the DoD to more accurately estimate the noise environment from aircraft range operations and will provide a scientific foundation for range commanders in addressing criticisms from knowledgeable citizens on the appropriateness of these estimates. These tools will assist the DoD in being responsive to the requirements of the National Environmental Policy Act (NEPA), while protecting operational readiness from unreasonable restrictions based on today's limited knowledge of air-gunnery noise effects.

Air Gunnery Noise Model