Авіаційно-космічна техніка та технологія (Aug 2024)
Acoustic radiation of a ducted UAV propeller
Abstract
The subject of this study was the acoustic radiation of the ducted propeller of an unmanned aerial vehicle. The object of this study was the ducted propeller of a quadcopter. The peripheral diameter of the propeller was 128 mm, and the thickness of the duct was 2 mm. The propeller rotates with the duct. The purpose of this work was to assess the influence of the duct on the acoustic radiation of the propeller of an unmanned aerial vehicle. The following tasks were set and solved in this work: a comparison of the sound pressure level values of the open and ducted propeller of an unmanned aerial vehicle; visualization of sources of broadband noise from the ducted propeller. The flow in a ducted and open propeller was studied using the numerical experiment method. The sound pressure level was calculated in the near acoustic field (radius 1 m) by summing the acoustic radiation of the first six harmonics. To visualize the noise sources, a broadband noise model was used, derived from Proudman's formula, which calculates the total sound power. Results: Based on modeling the flow in the open and ducted propeller of an unmanned aerial vehicle, values of the sound power level were obtained for each operating mode studied. In all studied operating modes at a rotation speed of 3000...10000 rpm. The acoustic pressure level of the unmanned aerial vehicle propeller was significantly reduced due to the use of a duct. The greatest noise reduction corresponds to lower speeds. A ducted propeller has an acoustic radiation of 6.97 dB–6.3 dB lower than an open propeller in the rotation speed range of 3000...10000 rpm. Visualization of sources of broadband noise during flow around an unmanned aerial vehicle with its duct propeller shows that the main source of broadband noise is the duct. Zones displaying broadband noise are available on both the lower and upper edges of the duct. The scientific novelty and practical significance of the conducted research lies in the fact that new data were obtained on the effect of the ducted propeller of an unmanned aerial vehicle such as a quadrocopter on acoustic radiation. The obtained data will help create propellers for unmanned aerial vehicles with improved acoustic characteristics.
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