With the development of Unmanned Aircraft Systems (UASs), demand for Unmanned Air Vehicles (UAVs) is increasing worldwide. UAVs have been developed for a wide range of applications such as delivery, construction, entertainment, agriculture, and military purposes. With the technological development and the wide application range of UAV, the regulation of UAV altitude limits in many countries is further relaxed, and the problem of UAV noise pollution has emerged with the recent advent of the Urban Air Mobility (UAM) and Personal Air Vehicle (PAV) markets. In this study, one typical propeller, the 15X5 propeller of a T-motor, was analyzed by use of commercial computational fluid dynamics (CFD) software, ANSYS FLUENT V19.3. The effects of gravity and convection were analyzed to determine the noise characteristics at altitude using the FW-H equation. A high-altitude drone, which operates at heights from 0 to 10&nbsp;km with 1,000 to 5,000 revolutions per minute, was analyzed using the steady-state k-w SST turbulence model. And using the steady-state data to initialize values, a transient analysis was calculated with the LES turbulence model. The time step was divided based on the 1-degree rotational time, and the velocity residual on each axis was calculated until a value of 10-7 or less was achieved and no fluctuation of thrust, at which point it was considered converged. The CFD results were validated with the experimental data for thrust and the maximum error was 8.64%. The Overall Sound Pressure Level (OASPL) was calculated, and noise characteristics in the audible frequency range according to receiver points were also compared. Through this study, thrust and noise data according to altitude were provided. The aerodynamic and aero-acoustic characteristics at high altitudes that are generally difficult to measure by experiment are also presented. Therefore, considering the operational altitude of UAV, the appropriate operating altitude and rotational speed will be presented through the aero-acoustics analysis corresponding to that altitude, and the basic research data can then be applied to the upcoming UAS market.&nbsp;

Aeroacoustic Analysis of a UAV Propeller Operable at Various Altitudes

Paper Proceedings: https://asmedigitalcollection.asme.org/FEDSM/FEDSM2021/volume/85284

ASME 2021 Fluids Engineering Division Summer Meeting (FEDSM2021)

Supporting the need among researchers worldwide for additional online and multimedia content, ASME now offers the ASME Conference Video Collection. This platform will collect and provide long-term access to conference presentation videos, encompassing all technology areas within ASME's technical conference and events program. About 30,000-40,000 engineers across all mechanical engineering and related disciplines participate in ASME conferences each year. This includes authors of approximately 6,000 to 8,000 technical papers published by ASME, the majority of whom also submit video presentations for our virtual conferences. The video collection will be available as an add-on to existing product packages or as a separate subscription.