LES of the Flow and Acoustics Generated by a Wing Installed Aircraft Propeller Running in the Vicinity of the Ground

Moroianu, Dragos; Fuchs, László

doi:10.2514/6.2005-2905

Cited by 1 publication

(1 citation statement)

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“…While the major source of noise in the UAS is propellers, the propeller interaction with UAS structures has a significant contribution to the UAS noise signature, particularly for some of the novel multi-rotor UAS designs with hybrid configurations (e.g., quadrotor biplane tail-sitter VTOL [1]), in which propellers' wake and tip vortices might even interact with fixed wings used to enhance the UAS efficiency in forward flight mode. Such an interaction imposes unsteady loads on the UAS structure (wing and fuselage) and propeller blades, which are the source of the structure-born noises and alter the noise level [23][24][25][26][27][28][29][30][31][32]. In an experimental study, Sinnige [29] found that for a tractor configuration of a propellerwing-nacelle system, the noise due to the propeller-wing interaction may be reduced by decreasing the propeller loading, because the blade tip vortices are the main source of structure-born noise.…”

Section: Introductionmentioning

confidence: 99%

A Computational Study on the Aeroacoustics of a Multi-Rotor Unmanned Aerial System

2021

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The noise generated by a quadrotor biplane unmanned aerial system (UAS) is studied computationally for various conditions in terms of the UAS pitch angle, propellers rotating velocity (RPM), and the UAS speed to understand the physics involved in its aeroacoustics and structure-borne noise. The k-ω SST turbulence model and Ffowcs Williams-Hawkings equations are used to solve the flow and acoustics fields, respectively. The sound pressure level is measured using a circular array of microphones positioned around the UAS, as well as at specific locations on its structure. The local flow is studied to detect the noise sources and evaluate the pressure fluctuation on the UAS surface. This study found that the UAS noise increases with pitch angle and the propellers’ rotating velocity, but it shows an irregular trend with the vehicle speed. The major source of the UAS noise is from its propellers and their interactions with each other at small pitch angle. The propeller and CRC-3 structure interaction contributes to the noise at large pitch angle. The results also showed that the propellers and structure of the UAS impose unsteadiness on each other through a two-way mechanism, resulting in structure-born noises which depend on the propeller RPM, velocity and pitch angle.

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