Numerical simulation analysis of droplet spraying by an agricultural hybrid wing unmanned aerial vehicle

Agricultural Unmanned Aerial Vehicles (UAVs) mainly leverage the downwash airflow generated by rotors for spraying. However, due to the inherent instability of the downwash airflow, there may be droplet drift problems. Computational fluid dynamics is used to investigate the behavior of droplet deposition in the downwash flow field of an agricultural hybrid wing UAV under different operating conditions. The results indicate that as the height increases, the deposition distribution of droplets becomes more uniform, and the drift problem is also improved. Compared with the quadrotor UAV, hybrid wing UAVs have a faster downwash airflow velocity, which helps achieve a more uniform distribution of droplets. However, the phenomenon of “negative velocity channels” is more pronounced and may lead to additional droplet drift. When UAVs encounter crosswinds during spraying, it can ensure a uniform droplet distribution by increasing the rotor velocity. The findings reveal the deposition behavior of sprayed droplets under different operating conditions and provide a reference for the practical operations of UAVs.