Modeling of Urban Air Mobility Noise to Enable Innovative Means of Noise Reduction

Project Number: 049
Category: Noise, Tools

The goal of this project is to develop an acoustic modeling approach for future Urban Air Mobility (UAM) and electric Vertical Take-Off and Landing (eVTOL) vehicles that will enable assessment of the wide variety of proposed concepts in this design space and address the configuration and operation of such vehicles for low noise impact near vertiports and during enroute operations.

The prediction capability must be a first principles approach because these vehicles are significantly different in configuration and operation than existing general aviation, helicopter, or tiltrotor vehicles. The proposed configurations all envision some sort of vertical take-off with lift rotors and/or tilting rotors, but unlike helicopter rotors, these rotors are likely to be fixed pitch devices (no collective or cyclic pitch controls) that operate at variable rotation speeds to provide the varying lift required to hover and during transition to winged flight. These vehicles are also likely to have many rotors and propellers – and some may have shrouds surrounding the rotors all driven by electric motors. For such complex configurations, it is likely that unsteady aerodynamic and acoustic interactions may be more important than for traditional vehicles. Furthermore, low noise operations will require optimization of the vehicle trim – from hover, through transition, and in winged flight. The envisioned noise prediction tool will be an extension of the noise prediction system developed in two ASCENT Projects: Project 6: Rotorcraft Noise Abatement Operating Conditions Modeling and Project 38: Rotorcraft Noise Abatement Procedures Development. The noise prediction tool will be used to provide baseline noise profiles for notional UAM and eVTOL aircraft. Flight profiles and operating procedures will be simulated to demonstrate the potential of low noise design and operations.

Outcomes

This project is anticipated to provide the FAA crucial information to begin the assessment of the noise characteristics of UAM and eVTOL aircraft in a quantifiable manner. Specifically, first principles noise predictions of complex aircraft will be able to provide a realistic representation of the noise levels, directivity, and characteristics, which can ultimately be incorporated into AAM and AEDT. Analysis of notional vehicles will provide the FAA information that is independent from manufacturers, before manufacturer flight test or certification noise data is available. Configuration and operation analysis will provide target noise values for all flight operations.

Last Updated 4/12/2023

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