Source Noise Model for Rotorcraft Operations Planning

US warfighter safety could be improved by providing an ability to quickly and accurately assess the acoustic impact of rotorcraft operations in the field and reduce the likelihood of detection. ĀCurrent mission planning tools are empirical in nature, limited to operating conditions for which flight test data exists and challenged in predicting the acoustic impact of maneuvering flight.Ā First-principles models capable of predicting source noise beyond the range of test data cannot produce helicopter noise spheres with the accuracy required by mission planners.Ā The solution proposed here is to develop a time-domain based hybrid method, in which a mid-fidelity, physics-based helicopter aeroacoustic model is calibrated to measured data using parameter identification techniques to provide comparable accuracy to current empirical models where measured data exists and superior accuracy for flight conditions where measured data does not exist.Ā The new method will support accurate extrapolation from steady flight data to maneuvering flight and to different density altitudes and gross weights.Ā Existing, validated, mid-fidelity, helicopter aeroacoustic prediction software will be calibrated to measured data using parameter identification methods tailored specifically for this application leveraging and expanding upon experience gained in directly-related prior work.