Investigation on the transient aerodynamics of a tube-launched unmanned aerial vehicle with a span-extended wing

Span morphing wings are designed for unmanned aerial vehicles to improve aerodynamics and flight performance. The aerodynamic analysis mainly focuses on the quasi-steady performance of span-morphing wings under several typical configurations. However, the aerodynamic characteristics become unsteady and dynamic during the morphing process. This work, therefore, performs a numerical study on the transient performance and the mechanism of a tube-launched aircraft with a span-extended wing. The numerical results show that the transient aerodynamic force creates a dynamic hysteresis loop surrounding the quasi-steady data. The relative deviation in the drag is larger than in the lift, and the hysteresis effect of the flow field is the major contributor. It changes the force distribution by affecting the formation of the wingtip vortex. This work can provide a reference to the design of tube-launched UAVs.