基于DMD方法的超声速进气道喘振特性分析

Characteristics investigation on supersonic inlet buzz with dynamic mode decomposition method

采用非定常数值仿真方法对典型超声速进气道的喘振现象进行了研究,并引入动力模态分解(DMD)方法对小喘和大喘流动特性进行了分析,获取了小喘及大喘的流场振荡特征,其中DMD得到的1阶模态反映了时均流场特征、2阶模态反映了主频振荡流场特性。在此基础上,针对小喘与大喘的相互关系进行了研究,结果表明:进气道内小喘流动包含大喘的流场振荡特性,小喘状态是进气道由不喘到大喘状态的中间状态,由小喘向大喘演化过程中,进气道内一些流动特征逐渐减弱并趋于稳定收敛,大喘的流场结构整体上比小喘状态更为稳定。

Buzz phenomena of a typical supersonic inlet were studied with numerical simulations.The dynamic mode decomposition(DMD)method was introduced to analyze the flow characteristics of the little buzz and big buzz.The first order dynamic mode reflected the time-averaged flow field characteristics,and the second order dynamic mode showed the flow field features of the main frequency oscillation.In addition,the research on the relationship between little buzz and big buzz reveals that the flow of little buzz contains the oscillation characteristics of the big buzz,and little buzz regime is a transitional state from the steady flow field to the big buzz regime.During the evolution from the little buzz to the big buzz,some flow structures in the inlet are gradually weakened and tend to be stable,hence the overall flow field of the big buzz is more stable than that of the little buzz.