The prominent features of the primary instabilities of a turbulent source flow between finite-span parallel rings with spatially modulated inflow conditions rotating at angular rate $\Omega$ are investigated. Two different two-dimensional instabilities that occur at large (${\alpha }_Q\gtrsim 1.00$) and low (${\alpha }_Q\lesssim 0.65$) flow rates have been traced back to two different physical mechanisms related to jet-wake and mean-core flow, respectively. The effect of the radial aspect ratios $\Gamma$ on the instability characteristics of the flow between parallel rings is also considered in this paper. Numerical URANS simulations are conducted for three different radial aspect ratios, i.e. $\Gamma =1.25$, 1.5, and 2, the corresponding cross-sectional aspect ratios $\Lambda =2(\Gamma -1)\times 3.325$, and two conceptually different inflow conditions. Their impact on the rotating instabilities in terms of instability mode number and instability frequency is the main focus of this study and is analyzed by fast Fourier transform (FFT) and wavelet analysis. Realistic inflow conditions with a leakage flow are found to overtake the instability for small radius ratios and affect the primary instabilities for large radius ratios.

具有以角速率旋转的空间调制流入条件的有限跨平行环之间的湍流源流的主要不稳定性的突出特征$\Omega$被调查。大量发生的两种不同的二维不稳定性（${\alpha }_{问}\gtrsim 1。00$）和低（${\alpha }_{问}\lesssim 0。65$）流速可追溯到分别与喷射尾流和平均核心流相关的两种不同的物理机制。径向纵横比的影响$\gamma$本文还考虑了平行环之间流动的不稳定特性。URANS 数值模拟针对三种不同的径向纵横比进行，即$\gamma =1。25$、1.5、2，对应的横截面长宽比$\Lambda =2（\gamma -1）\times 3。325$，以及两个概念上不同的流入条件。它们对旋转不稳定性在不稳定模式数和不稳定频率方面的影响是本研究的主要焦点，并通过快速傅里叶变换（FFT）和小波分析进行了分析。发现具有泄漏流的实际流入条件克服了小半径比的不稳定性并影响大半径比的主要不稳定性。