A Method to Measure and Model Acoustic Emissions of Multicopters

Area of Science:

• Acoustics
• Aerospace Engineering
• Environmental Science

Background:

• Increasing commercial use of Unmanned Aerial Vehicles (UAVs) necessitates understanding their environmental impact, particularly noise pollution.
• Existing methods for assessing UAV noise are insufficient for comprehensive environmental impact evaluations.

Purpose of the Study:

• To develop and validate a method for measuring and modeling the sound radiation of multicopters.
• To establish a simplified procedure for predicting multicopter noise emissions.

Main Methods:

• Utilized a multiple regression approach based on sound emission measurements.
• Determined the directivity pattern during stationary hover flight.
• Developed a rotational speed-dependent sound emission model for hover.
• Introduced a multicopter-specific correction term for forward flight conditions.

Main Results:

• The directivity pattern of multicopter sound radiation was found to be largely independent of rotor speed and flight procedure.
• A simplified measurement procedure for stationary hover flight was established.
• A predictive model incorporating hover and forward flight conditions was validated with field measurements from three multicopter models.

Conclusions:

• The proposed method simplifies the measurement and modeling of multicopter noise.
• This approach provides a foundation for assessing the acoustic impact of commercial Unmanned Aerial Vehicles.
• Accurate noise prediction is crucial for the responsible integration of multicopters into various applications.