Computational Methodology to Compute Unmanned Aircraft Deflections due to Aerodynamic Interaction with a Commercial Aircraft

Abstract

This paper describes the study of the possibility of a small Unmanned Aircraft System (UAS) deflecting away from a collision path with a large transport category aircraft due to the influence of only the aerodynamic flow field of the aircraft. The manned aircraft model used in this study is the Common Research Model (CRM) aircraft. The small unmanned aircraft (UA) model used in this study is representative of the DJI Phantom III drone. The authors obtained the UA deflections by performing a series of trajectory analyses in which the small UA is placed on a collision path with the manned aircraft at two different locations on the wing. The first impact location is selected near the mid-span of the wing, and the second near the root of the wing. The aircraft operating conditions are based on a low-altitude holding flight pattern. The trajectory analysis is performed using Computational Fluid Dynamics (CFD) methods coupled with a six-degrees-of-freedom (6-DOF) solver. The authors determined that the vertical deflections are not large enough for the small UA to deflect away from the intended impact location for any of the four impact scenarios described in this paper. The change in orientation of the small UA at the time of impact with the aircraft is observed to be insignificant in three of the four impact scenarios. It is observed that a higher relative speed and a higher CRM aircraft angle of attack results in slightly larger vertical deflections and greater changes in the orientation of the small UA at the time of impact with the aircraft.