Effects of Geometric Nonlinearity on the Gust Responses of Near-Space Solar-Powered Vehicle Landing Phase

The near-space solar-powered aircraft was taken as the research object in this study, which was characterized by lightweight, high flexibility and low landing speed. Based on the CFD/CSD loosely coupled analysis method, the grid velocity method was employed to introduce gust loads, and the effects of geometric nonlinearity on the static equilibrium state and gust load state during landing phase of near-space solar-powered aircraft were investigated. The influence of geometric nonlinearity on the structure and aerodynamic performance of the aircraft during landing phase was revealed. The results showed that after the gust response of the aircraft reached its peak, the lift coefficient, the structure bending moment of wing root, and wingtip displacement obtained without considering the geometric nonlinearity of the aircraft did not recover to the static equilibrium state, and the wingtip had a Z-direction displacement of −0.18 m and the maximum counter-twist of 3.3°. The calculation results considering geometric nonlinearity were more consistent with the actual situation of various aircraft parameters. Therefore, the geometric nonlinearity of the structure should be taken into account when analysing the gust response of near-space solar-powered aircraft during landing phase.