Numerical Modeling and Analysis of a Multi-rotor UAS

Unmanned Aircraft Systems (UASs) are gaining a lot of importance due to their inherent advantage of operating the aircraft with no onboard pilot. Though there are single and multi-rotor UASs, the later one is a popular choice for operations like surveillance and seed sowing in agriculture. This work emphasizes on carrying out computational fluid dynamic (CFD) simulations for investigating the flow around a quadcopter (UAS with four rotors) for different angles of attack (AoAs). Phenomena such as vortex formations and wake regions are studied. Quadcopter chosen for this work is a topology optimized 3D printed model. Numerical wind tunnel simulations are carried out for different wind velocities. Influence of relative propeller motion on each other is also studied. Stability of the quadcopter during lift and hovering stages is examined. From the results, it is observed that the stability of the quadcopter is dependent on the combination of AoA and velocity. Further, at lower ground clearances, the quadcopter is more stable than at higher altitudes because of the flow pattern.