Experimental Methods for UAS Propeller Noise Source Identification

Advanced Air Mobility (AAM) aircraft leverages electric propulsion with multiple rotors for urban transport. Similar configurations are also found in Unmanned Aircraft Systems (UAS), which are increasingly being used in many industries for observation, inspection, and intervention. Although electric motors are quieter than traditional engines, noise from rotor aerodynamic interactions remains a major challenge. A collaborative research initiative between ÉTS, Université de Sherbrooke (UdS) and University of Toronto Institute for Aerospace Studies (UTIAS) investigates propeller noise mechanisms through experimental and numerical methods. The goal is to develop improved noise prediction tools for propeller design, in particular advancing understanding and modeling of low Reynolds effects and blade vortex interactions that are typical of UAS propulsion.

This specific research project will investigate flow transition by means of advanced measurements of wall pressure and friction fluctuations on flat-plates and airfoils and examine its relation with the aeroacoustic noise emission of airfoils. Additionally, the candidate will use phased microphone array technology to pinpoint noise sources on airfoils and several open and ducted propellers. This technique will allow the identification and quantification of flow transition and tip vortex interactions. The experimental campaigns will enable reference measurements to be collected for the validation of numerical simulations performed by other partners. Finally, the candidate will contribute to improved aeroacoustic models for propeller noise predictions, a path towards the development of quieter UAS.

This collaborative program involves five academic partners who will contribute their specific expertise to support the candidate training and learning and facilitate the experimental campaigns development. In particular, part of the research will be conducted at the research facilities of UTIAS and UdS over extended periods. Regular meetings will be held with the partners and all students involved in the program.