基于本征正交分解方法的多段翼型流动分析

对多段翼型流动结构的深入刻画和理解对于多段翼型的外形设计来说十分重要.在数值模拟的基础上,运用本征正交分解(proper orthogonal decomposition,POD)方法对多段翼型的数值结果进行重构和分析,对迎角变化情况下流动中的主要模态进行提取,并得到权函数随迎角变化的规律.针对嵌套网格的数值模拟流场的特点,通过对参与快照技术处理的数据进行筛选和还原,来避免无效数值对分析结果的影响.研究发现,流动中脉动流场所占的总能量比例相对较小,其整体POD能量谱收敛呈先快后慢的格局,大尺度的流动结构与流场中绝大部分的能量分布直接相关,且都包含在低阶模态中,而高阶模态则代表了复杂的脉动结构。

Proper Orthogonal Decomposition Method for Flow Analysis of Multi-element Airfoil

In-depth characterization and understanding of multi-element airfoil flow structure is important to the design of multi-element airfoil shapes.Based on numerical simulation,the proper orthogonal decomposition(POD) method was used for reconstruction and analysis of numerical results of the multi-element airfoil.With changes in the attack angle,the main modes of the flow are extracted,and their weight function with attack angle variation obtained.According to the simulation of flow field with an overlapped grid,a method that avoids ineffective impact on the analysis results is used by sifting the points in snapshots,and returning other points to the original position.It is found that the pulse stream flow sites account for a relatively small proportion of the total energy.The energy spectrum of the overall convergence of POD shows a slow-down pattern after a large-scale flow structure.Flow field in most of the energy distribution is directly related to the large scale flow sites included in the low-order modes,while the higher modes represent a complex pulse structure.