基于伴随方法的超声速客机机翼气动优化设计

Aerodynamic Optimization Design of the Supersonic Aircraft Based on Discrete Adjoint Method

采用基于RANS(Reynolds-averaged Navier-Stokes)方程的离散伴随方法,针对超声速客机构型开展了气动减阻优化设计研究。将自由型面变形(FFD,free form deformation)参数化技术、基于逆距离权重插值算法(IDW:inverse distance weighting)的网格变形算法和基于序列二次规划算法(SQP:sequential quadratic programming)的梯度优化算法等进行组装,建立了一套基于梯度的气动优化设计系统。通过该系统对超声速客机机翼实现精细参数化并基于此添加考虑结构要求及容积要求的厚度约束,继而进行了以全机阻力最小为设计目标的气动优化设计研究。设计结果表明,全机阻力减幅达到5.7%,机翼的激波区域得到有效抑制、激波强度明显降低,并且中外翼段压力分布形态表现出前缘吸力峰值降低,逆压梯度减弱,压力恢复更加平缓的特征。

The study on the aerodynamic optimization design of the SSA （ supersonic aircraft） is presented. And a gradient-based aerodynamic optimization system is build, which includes the FFD （free-form deform） parameteriza- tioN technique, the discrete adjoint technique based on RANS （Reynolds Averaged Navier-Stokes）equations, mesh deformation technique based on IDW（ Inverse distance weighting） and the gradient-based optimization algo- rithm based on the sequential quadratic programming. With the application of the system, the elaborate parameter- ization and thickness constraints considering structure and volume are realized on the SSA, leading to a aerodynamic optimization research aiming at the minimum of the aircraft drag. The results of optimization case shows that the aircraft drag is reduced by 5.7%, and the shock wave of the wing weakens, also, the pressure distribution in the mid and outer wing has a lower negative pressure peak of the leading edge, a weaker adverse pressure gradi- ent and a more gentle pressure recovery.