基于径向基函数网格变形的高速列车头型优化

AERODYNAMIC OPTIMIZATION OF HIGH-SPEED TRAIN BASED ON RBF MESH DEFORMATION

基于局部型函数三维参数化方法、改进的蚁群算法和改进的克里金(Kriging)代理模型,开展了列车头型的三维气动减阻优化设计研究.为了避免复杂几何外形大变形情况下千万量级网格的重复生成,提高高速列车头型优化设计的效率,引入了缩减控制点的径向基函数网格变形技术.优化结果表明:径向基函数网格变形技术在不降低网格质量的情况下可以有效缩短网格变形的时间消耗,能够用于复杂几何外形的气动优化设计;在给定的设计空间内,控制鼻锥外形的6个关键设计参数对列车气动阻力的影响呈单调递增关系;优化后,在满足约束条件的情况下,简化外形列车的整车气动阻力减小5.41%,头尾车减阻效果明显,中间车气动阻力基本不变.

An aerodynamic drag reduction optimization design study of high-speed train head is carried out based on the three-dimensional parametric approach of local shape function, improved ant colony algorithm and improved Kriging surrogate model. To avoid repeated generation of ten millions of meshes in the case of large deformation with complex geometry and improve the optimization efficiency of high-speed train head, we introduce mesh deformation techniques of the reduced control points based on radial basis functions （RBF）. The optimization results show that： RBF mesh defor- mation method could largely shorten the time-consuming of mesh deformation without reducing the quality of meshes, and can be used for aerodynamic optimization design of complex geometry. Under the design space given in this article, the six key design parameters that control the nose shape have effects on the aerodynamic drag of the train with a kind of monotonically increasing relationship. After optimization under the constraints, the total aerodynamic drag of the sim- plify shape is reduced by 5.68%. The aerodynamic drag of leading and trailing cars reduced a lot, while the aerodynamic drag of middle car changes little.