The flow field structure of a single injection port fluidic thrust vectoring nozzle was studied by introducing secondary flow injection in the expansion section of the two-dimensional convergent-divergent nozzle. To determine the motion characteristics of unsteady flow in a shock-induced fluidic vectoring nozzle, detached eddy simulation was conducted to simulate the three-dimensional flow field, and the flow mechanism in the nozzle was analyzed. Fourier mode decomposition was used to analyze the pressure coefficient on the symmetrical surface of the nozzle. Results show three natural frequencies in the flow field of the shock-induced fluidic vectoring nozzle. The first-order mode corresponding to frequency f 1 = 512.8 Hz mainly illustrates the oscillation of shock waves. The second-order mode corresponding to frequency f 2 = 2825 Hz illustrates the shedding of vortices. The third-order mode corresponding to frequency f 3 = 4650 Hz is similar to the second-order mode; however, the spatial scales of vortices decrease.

中文翻译：

---

单进样口流体推力矢量喷嘴中非定常流动的傅里叶模式分解

通过在二维收敛-发散喷嘴的膨胀段引入二次流喷射，研究了单喷射口射流推力矢量喷嘴的流场结构。为确定激激射流矢量喷管内非定常流动的运动特性，采用分离涡模拟法模拟三维流场，分析了喷管内的流动机理。傅里叶模式分解用于分析喷嘴对称表面上的压力系数。结果显示了激波诱导流体矢量喷嘴流场中的三个固有频率。频率f 1 = 512.8 Hz 对应的一阶模态主要说明冲击波的振荡。对应于频率 f 2 = 2825 Hz 的二阶模式说明了旋涡的脱落。频率f 3 = 4650 Hz 对应的三阶模态与二阶模态相似；然而，涡旋的空间尺度减小。