POD-Kriging降阶方法在串联双圆柱流场预测中的应用
POD-Kriging Reduced Method's Application in Tandem Cylinders' Flow

串联双圆柱是研究起落架噪声机理以及不同部件之间流动相互作用的经典算例，而距径比（圆柱柱心间距与直径的比值）是该构型非常重要的参数，随着距径比的改变，流场形态会发生明显变化。为更清晰地分析串联双圆柱流场的非定常效应和流场形态随距径比的变化规律，采用本征正交分解方法（POD）提取流场降阶基模态，再通过Kriging模型插值出待求的各模态投影系数，分别对串联双圆柱定参数非定常流场和变距径比时均流场建立降阶模型，为保证样本精度，快照数据的采集采用基于SST湍流模型的尺度自适应模型（SAS）。通过降阶模型预测的圆柱流场与数值计算及实验数据的对比，证明了模型的精度与效率，然后利用建立的降阶基总结了时均流场随距径比大小的变化规律。
The configuration of Tandem Cylinders is a typical one in researching noise and interactions between different components, where the distance-diameter ratio is a very significant parameter with which the flow form varies a lot. To clearly research the ratio's effect on tandem cylinders flow as well as the unsteady flow physics, a reduced-order model is built where Proper orthogonal Decomposition(POD) is usedto extract reduced basis modes, and Kriging model is used to train sample data and interpolate projection coefficents for each reduced basis. To ensure the snapshots' accuracy, the scale-adaptive simulation (SAS) model based on SST turbulence model is used to predict time-dependent flow field. By comparing with solutions provided by the numerical solver as well as experimental data, the reduced model presents a good accuracy and efficiency. And then based on the reduced basis, the change regulation of the time-average flow is summarized