基于直接控制FFD参数化方法的跨声速层流翼身组合体稳健性设计

Robust design of transonic laminar wingbody configuration based on direct manipulated FFD technique

自由变形技术(FFD)技术不是对几何外形的直接操作,进行精细化设计时需引入高阶FFD控制体,针对其在参数化几何外形时的局限性,开展了直接控制FFD参数化方法的研究.通过对基础外形典型剖面进行扰动,将扰动量通过参数识别反映到FFD控制节点上,反求控制节点的位移,有效地降低了高阶FFD控制体进行三维外形参数化时设计变量的个数,并且将典型剖面参数化与三维外形灵活结合,更具物理直观性.运用此参数化方法结合四元数网格变形技术,采用γ- Reθt转捩模型进行边界层数值转捩模拟,多种群协作粒子群算法以及自适应采样技术构建稳健性优化设计系统,运用该系统对于跨音速层流翼身组合体进行了稳健性设计,设计结果表明,优化后的翼身组合体在马赫数不确定性范围内不仅可以保持大范围的层流区域,还可以控制激波缓慢发展,具有较好的稳健性.

The geometric shape is not directly manipulated by free-form deformation （FFD） technique. A high level FFD control volume is always adopted in the refined aerodynamic design. The direct manipulated free-form deformation （DFFD） technique is developed in this paper to improve the shortcomings of the FFD technique. This method adopt a parameter identification technique which can identify the disturbance quantifies and convert them into displacement values on the FFD control lattices. The DFFD technique can accomplish refined aerodynamic shape design using less design variables. The visual impression is much better than the traditional FFD technology, and the number of the design variables is not increased with using of the high level FFD control volume. The robust design system is established by DFFD technique, multi-groups collaboration particle swarm optimization （MCPSO） and adaptive sampling algorithm, combined with quaternion mesh deforming technique and the numerical simulation of boundary layer transition based onγ-Reθt^- transition model. A transonic laminar wing body is optimized by this system. The design results show that not only a wide range of laminar flow area is maintained, but also the development of shock is controlled.