A major innovative thrust in urban air mobility (UAM) is underway that could potentially transform how we travel by providing on-demand, affordable, quiet, and fast passenger-carrying operations in metropolitan areas using novel air vehicles that employ Distributed Electric Propulsion (DEP). NASA is supporting the development of technology required for the success of these new UAM aircraft in which improved methods for acoustic modeling play a large role. Safe and quiet operation are critical to public acceptance. The proposing team intends to strongly leverage our recent major advances in the modeling and analysis of DEP UAM aircraft by enhancing our existing state-of-the-art DEP aircraft flight simulation, aeromechanics and acoustics analysis software with improved capabilities for modeling noise sources of specific importance to DEP UAM aircraft. In Phase I, leveraged software was enhanced and demonstrated by performing acoustic predictions with high fidelity aeromechanics for a multirotor UAM aircraft in hover and transition flight with time-varying RPM on eight rotors. The goal of the Phase II effort is to develop and deliver commercial-grade, comprehensive acoustic analysis for UAM aircraft, that would provide fast, accurate prediction of critical acoustic characteristics associated with DEP UAM aircraft, including (1) noise generated by the simultaneous operation of multiple, variable RPM rotors and props, (including coaxial rotors), (2) interacting rotor/prop/wing/airframe noise, (3) broadband noise pertinent to eVTOL UAM aircraft, (4) noise due to inflow turbulence from a variety of sources, and (5) electric motor noise. The final software will include both a stand-alone analysis and, of significance, a flight simulation able to predict the acoustic impact of UAM aircraft control strategies during general maneuvering flight within realistic wind/turbulence environments during take-off, landing and cruise.
The comprehensive acoustic analysis proposed for development would enable accurate prediction of acoustics of UAM aircraft in computation times commensurate with daily design work, directly supporting NASA’s ARMD Strategic Thrust #4 - Safe, Quiet, and Affordable Vertical Lift Air Vehicles in the NASA Technology Roadmap. The developed analysis would be of immediate use to NASA and the UAM entrepreneurs NASA supports in evaluating and designing low-noise UAM air-taxi configurations and identifying methods to reduce noise of UAM vehicles.
CDI collaborates with many UAM vehicle developers with an immediate need for a comprehensive acoustic analysis for DEP UAM aircraft. The analysis will also be of great value to the FAA for use developing acoustic certification criteria for UAM air taxis, and the DoD and major rotorcraft manufacturers in analyzing acoustic characteristics of future vertical lift (FVL) concepts.