静稳定裕度对飞翼布局的影响研究

减小配平损失对于提高飞翼布局升阻比和提升飞行控制能力具有重要意义，因此基于离散伴随优化方法研究静稳定裕度对跨音速飞翼布局减阻优化的影响，分别开展10%，0%，-10% 三种静稳定性设计工况的优化研究。采用自由变形（FFD）方法对非结构表面网格进行参数化，以FFD 控制点为设计变量，通过求解流场和伴随方程得到灵敏度信息；采用序列二次规划SQP 算法获得控制点位移的梯度，然后经过多轮迭代得到优化构型。结果表明：在几何厚度和力矩配平的约束下，离散伴随优化方法可以显著提升飞翼布局的最大升阻比，三种工况下最大升阻比提高都在8% 以上；随着静稳定性裕度减小，定升力系数优化的巡航升阻比增量有所减小，当静稳定裕度为10% 时巡航升阻比提高了5.08%。

Research on adjoint optimization for flying wing configuration of stability margin

The influence on aerodynamic optimization of flying wing configuration is studied based on discrete adjoint method, which 10%, 0%, -10% stability margin are considered in the optimization process, respectively. The free-from deformation (FFD) technique is used to achieve the parametrization of surface unstructured grid, the control point of FFD is selected to serve as design variable, then flowfield and adjoint equation is solved to obtain objective values and residual, the sequential quadratic programming(SQP) algorithm is utilized to obtain the gradient of control points, the final configuration is obtained by multiple iteration. The results show that the adjoint optimization can evidently improve the maximum lift-to-drag ratio under the constraint of geometric thickness and moment trim, and the increment exceeds 8% at these three conditions. The increment of cruise lift-to-drag ratio appears to reduce with the increase of stability margin while lift coefficient is fixed, the lift-to-drag ratio can increase 5.08% when the stability margin is 10%. Therefore, the optimization with higher stability margin can reduce can reduce trim drag and increase cruising lift-to-drag ratio to improve the flight performance of flying wing.