Aerodynamic Interaction Studies on Amphibious Vehicle in Forward and Hovering Flight

Unmanned aerial vehicles (UAVs) have gained a lot of attention in recent times due to its versatility in deployment for multifaceted operations. The development of amphibious UAVs with inculcating the features of hovercraft and multi-rotor has tremendous impact on military, naval and coastal guard applications. Stability and performance of this kind of vehicle highly depend on aerodynamic interaction of multirotor with respect to various wind conditions. The present study focuses on performing computational fluid dynamic (CFD) analysis on examining the vortex formation, turbulent regimes, wake region, tip vortex formulation and ground effect.Preliminary flow analysis is performed to determine the angle of attack (AoA) and wind speed on which minimal drag is experienced by the amphibious structure. Further, analysis conducted through varying the relative velocity of the vehicle and changing the speed of the propellers. The pressure distribution across the fuselage and rotor surface predicted the stability of the vehicle. The ground effect is examined through varying the clearance between the vehicle and ground surface with respect to a multiplicity of rotor diameter. CFD analysis results suggested that at 5° AoA and 8.3 m/sec the designed amphibious vehicle yielded superior performance characteristics and stability.