中文摘要：

为分析非定常流动控制技术抑制分离流的机理,对弯曲扩压通道的试验模型进行了数值模拟,针对扩压通道在无控和采用最佳射流频率状态下的计算结果引入了动力模态分解（DMD）技术进行分析。通过DMD技术能够将包含时空信息的扩压通道复杂流场进行分解,捕获流场包含的动力信息和对应的拟序流动结构。将无控和有控流场分解的结果进行对比分析后表明：采用有效激励措施时,和脱落涡频率一致的涡系对流场的影响更加突显,流场整体上表现得更加有序;非定常控制抑制了一部分涡的增长,使得各模态整体上更加稳定;而有控流场占主导地位的涡系结构相比无控流场较为有序,且对主流区未形成明显的直接影响。

英文摘要：

To analyze the mechanism of depressing flow separation with unsteady flow control technology,a numerical simulation for the experimental model of the divergent channel is carried out.Dynamic mode decomposition（DMD）technology is adopted to study the flow field of the curved divergent channel with and without pulsed jet control.With DMD technology,the complex flow field of the divergent channel containing spatial and temporal information can be decomposed hierarchically,and dynamical information as well as spatial coherent structure corresponding to the vortex can be captured and rendered.A comparison of the decomposed flow fields with and without control shows that with effective excitation,the coherent structure with the frequency approximating the frequency of the shedding vortex becomes more dominant in the initial flow field,and the overall flow field turns out be to more ordered.Some coherent structures,decomposed from flow field without control,are suppressed to make all modes more steady.The dominant structure of the controlled flow field has no obvious influence on the main flow.