为研究倾转旋翼机近地状态下旋翼-机翼的气动干扰特性，基于嵌套网格技术和RANS/LES(Reynolds-Averaged Navier-Stokes/Large Eddy Simulation)混合方法建立了一套高分辨率流场模拟框架，重点探讨不同离地高度下旋翼-机翼气动特性的变化，结果表明：地面和机翼的存在阻滞了旋翼下洗流发展，显著改变了旋翼尾迹的演化过程，桨尖涡径向位置整体呈现出先收缩后扩张的趋势，而轴向位置迁移速率减慢；旋翼拉力随离地高度减小而增大，机翼下洗载荷随离地高度减小而减小，相较于无地效状态，旋翼拉力最大提升6.20%，悬停效率最大提升8.40%，机翼所受下洗载荷下降幅度达59.05%。针对近地流场涡系结构演化过程，采用四阶龙格-库塔时间推进方法和四阶中心差分格式构建了拉格朗日拟序结构的计算方法，通过计算不同时刻有限时间李雅普诺夫指数场阐明了地面效应下旋翼-机翼流场中涡结构的时空演化过程，揭示了回流结构通过流体微团的持续输运维持其稳定性的物理机制以及对桨尖区域产生的下洗作用导致气动力减小的流动机理。
To investigate the aerodynamic interference characteristics between rotor and wing of the tiltrotor aircraft in ground effect, a high-resolution flow field simulation framework was established based on the overset technique and hybrid RANS/LES(Reynolds-Averaged Navier-Stokes/Large Eddy Simulation) method. This study focuses on investigate the variations in aerodynamic characteristics of the rotor-wing in varying heights above the ground. Results demonstrate that the presence of the ground and wing inhibits the development of rotor downwash, significantly altering the wake evolution process. Compared to out of ground effect condition, the radial position of tip vortices exhibits an initial contraction followed by expansion, while the axial migration rate decreases. With rotor thrust increasing and wing download decreasing as ground height decreases, compared to the out of ground effect condition, rotor thrust and figure of merit increase by up to 6.20% and 8.40% respectively, while wing download drops by as much as 59.05%. A computational method for Lagrangian coherent structures was developed using a fourth-order Runge-Kutta time integration and fourth-order central difference scheme to investigate the evolution of vortical structures in ground flow fields. By computing finite-time Lyapunov exponent fields at different instants, the spatiotemporal evolution of the vortex structures within the rotor-wing in the ground flow field was clarified. This revealed the physical mechanism by which recirculating structures maintain stability through continuous transport of fluid parcels, as well as the flow mechanism leading to reduced aerodynamic forces in the tip region due to downwash effects.
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