Drag Reduction Investigation On High-Wing Aircraft Landing Gear Fairing

The CFD-based aerodynamic design using Navier-Stokes plays an important role in the aerodynamic shaping of complex surfaces and flow control effect study. The research is focused on the aerodynamic shape redesign of high-wing aircraft landing gear fairing using proper parameterization and also to adopt a good flow control method for drag reduction.High-wing aircraft generally has a big landing gear fairing, thereby its shape needs to be designed carefully in order to reduce drag as much as possible. In order to understand the aerodynamic effect of landing gear fairing, guiding the following fairing shape redesign and determine the drag reduction magin, a contrast is made between the configurations with fairing and the one without fairing. Then considering the landing gear layout restraint, a NURBS parametric modeling method within CATIA is proposed and implemented to redesign the shape of landing gear fairing. During the redesign process, some useful aerodynamic characteristics about this type of landing gear faring are concluded. CFD results indicate the drag is reduced by 1.9 Counts, about 27% of the whole drag reduction margin. Results shows that the design method adopted is effective in solving the problem of complex shape redesign. The advantages of the proposed method lies not only in the flexibility landing gear fairing modeling, but also in its capability to adapt quickly to the evolution of design requirements during the design process.Moreover, in order to understand the fairing effect more clearly, a deformation without landing gear constraints is performed. The results show the negative effect of fairing can be concluded as the disturbance to the wing, and the raising extent of the faring along wing span affects the whole configuration most. Finally, a passive flow control method is introduced owing to the chaotic flow in the wake of the faring; a strake is designed and installed behind the original fairing. Results show the strake has a good control of the flow, the total drag can be reduced by 0.9 Counts.