CFD Analyses of the Aerodynamic Effects on a Quadcopter Propeller in the Proximity of Fixed and Horizontal Moving Obstacles

Quadcopters are a type of drone with four rotors that are used for a variety of purposes, such as freight transportation, military surveillance, and aerial photography. However, when operating around obstacles and in the proximity of walls or moving objects, the aerial vehicle can be subject to external forces that can cause severe flight instability. To address this issue, a methodology based on multiple reference frame (MRF) tetrahedral meshes is developed in this paper and applied to computational simulations to study the downwash flow generated by a quadcopter propeller over fixed and moving obstacles. The effects of different rotational speeds and moving obstacle proximity are assessed and compared to experimental data and theoretical models. The results show that the presence of fixed and moving obstacles can have a significant impact on the aerodynamic performance of the propeller, leading to changes in lift force and the formation of turbulent vortices and flow separation zones. When hovering at 3000, 5000, and 9550 rpm, the results showed an increase in the lift force on the propeller by 9.3%, and 1.03% compared to open rotor thrust due to the presence of a fixed obstacle (wall) placed at 0.1 m and 0.2 m from the propeller respectively. However, when hovering (3000 rpm) at 0.2 m above a moving obstacle (5 m/s, and 10 m/s) the results have shown an increase in the lift by 1.92% for 5 m/s moving obstacle, and then a decrease by 4.4% for 10 m/s, comparing to fixed obstacle thrust. Finally, these findings could be useful for improving the stability and performance of quadcopters in real-world environments.