Impact of UAV rotor downwash on atmospheric parameter measurement

Multirotor Unmanned Aerial Vehicles (UAVs) possess flexible maneuverability and can be equipped with various sensors to achieve real-time monitoring of atmospheric parameters such as temperature, humidity, pressure, and wind fields. They have been widely applied in the field of atmospheric parameter measurement. However, the disturbed flow field induced by the rotation of the rotor interferes with the atmospheric environment around the UAV, compromising the accuracy of sensor measurements. Therefore, this study employs a Computational Fluid Dynamics (CFD) approach to systematically analyze the characteristics of the three-dimensional flow field distribution of the UAV under hover conditions (0 m/s) and two environmental wind speed scenarios (2 m/s with 0° UAV tilt angle, 8 m/s with 5° UAV tilt angle). The simulation results indicate that, under hovering conditions with calm wind, the rotor-induced wind speed in Zone A at a distance of 1.0 m from the airframe attenuates to below 0.5 m/s. When the environmental wind speed is nonzero,regardless of the scenario, the wind speed measurement error at 1.0 m from the airframe in Zone A can be controlled within ±0.5 m/s. Due to the significantly superior flow field stability in Zone A of the UAV compared to other zones, the placement of the sensor in Zone A is identified as the optimal configuration. This study provides a theoretical basis for sensor placement in practical atmospheric measurements using UAVs and highlights key areas for future research.