Investigating UAV Propellers Performances Near Moving Obstacles: CFD Study, Thrust Control, and Battery Energy Management

Abstract

Quadcopters are widely used in military and civilian applications, but when flying near moving objects, they may encounter flight instability. This study investigates the flow aerodynamic interference of two drones' propellers when they hover near moving obstacles using CFD simulations. An unstructured mesh is used with frame motion to model the propeller's rotation. Different altitudes, rotational speeds, and obstacle velocities are tested to understand their aerodynamic effects on the propeller's performance. The results indicate that hovering 0.1 m above a fixed obstacle at 9550 rpm increased lift by 9.28%. This decreased by half when propellers were positioned adjacent to each other. Besides, a moving wall below the propellers at various velocities significantly affects the thrust and power variation of the propellers at low hovering speeds. For example, when hovering at 3000 rpm over a moving wall at 10 m/s, the thrust on one side of the UAV decreases by 8.51%, leading to flight instability. Different thrust control strategies and flight scenarios are performed to ensure flight stability and energy management. Finally, thrust control strategies prove crucial in stabilizing thrust and altitude, but power consumption increases by 12.8%, requiring 30% more energy required under specific flight scenarios near moving obstacles.