基于响应面法的低速翼型气动优化设计

Aerodynamic optimization design of low-speed airfoil based on response surface methodology

响应面方法相较于其它直接优化方法有其高效、实用的优势,此前的研究更多地将响应面方法用于超音速和跨音速翼型的减阻优化设计中。本文将此方法应用于低速翼型优化设计中,进行了基于RANS(Reynolds-Aver-aged Navier-Stokes)方程和自由转捩预测耦合求解的低速翼型气动优化设计。通过计算附面层方程得到附面层参数并用en方法计算转捩位置,并考虑了T-S波和层流分离造成的转捩。RANS方程计算中,使用了转捩过渡区模型,以保证附面层外边界压力分布的精度。RANS方程和转捩预测迭代进行至转捩位置收敛。在响应面模型计算中,使用不含二阶交叉项的二阶多项式模型,减少了构造模型所需的计算量;合理的选择设计空间保证了构造的响应面模型具有较高的精度。使用三个设计点的多目标优化设计,保证了设计的合理性。通过对NACA64(1)-112翼型优化计算结果表明,本文的方法可以有效地进行低速翼型的气动优化,各设计点上转捩位置也得到了改善,有较好的工程实用前景。

Response Surface Methodology（RSM） has some advantages over other direct optimization techniques.The previous studies using RSM mainly deal with transonic and supersonic body optimization.In this paper,RSM has been applied to obtain optimal shapes of low-speed airfoils based on coupling RANS equations and free transition prediction.In solving boundary-layer equations,boundary-layer properties are computed and used in the acceptable en method to obtain transition locations.In RANS code,transitional flow region is used.In constructing RS model,quadratic polynomials without the second-order cross items are employed and the accuracy of the approximation is not sacrificed when the range of design variables are carefully selected.The design results indicate that RSM could be successfully applied to three-point design to improve aerodynamic performance and transition locations of low-speed airfoils,and the overall computation burden is greatly reduced.