Recently, the particular energy separation of the vortex tube was thought to be caused by the energy transferred from the inner core stream to the outer periphery stream through the precessing vortex core, and the precessing frequency is a remarkable signal released by the vortex core. To study the basic distribution of the precessing frequency and the relationship between the frequency and energy separation, precessing frequency characteristics were analysed in a vortex tube with a diameter of 30 mm in this paper. To achieve this, axial velocity time series were obtained by LDV measurements. It is demonstrated that the impact of the precessing vortex core on the flow field is consistent under different radial positions at the same axial position. However, the impact gradually weakens downstream. In addition, the precessing characteristics vanish within the swirl decay zone, which results in the deterioration of the energy separation performance. An enhancement in the inlet pressure results in an improvement in the performance and a significant increase in the magnitude of the peak frequency. In addition, the energy separation process and performance under increasing inlet pressure were analysed. It was observed that the growth of the precessing frequency imparts a higher energy transfer capability, which results in higher performance. The patterns of large-scale vortices and energy separation of the vortex tube were determined based on these observations. In addition, the enhancement in the precessing frequency may offer a novel concept based on which the performance of the vortex tube can be enhanced. Finally, a large eddy simulation was recommended to obtain more detailed information on large-scale precessing vortices.

近来，涡旋管的特定能量分离被认为是由通过旋进涡旋核从内芯流传递到外周流的能量引起的，旋进频率是由旋涡旋涡核释放的显着信号。为了研究进动频率的基本分布以及频率与能量分离之间的关系，本文对直径为30 mm的涡流管进行了进动频率特性分析。为此，通过LDV测量获得了轴向速度时间序列。结果表明，进动旋涡芯对流场的影响在相同轴向位置的不同径向位置上是一致的。但是，这种影响逐渐减弱了对下游的影响。此外，旋涡衰减区内的进动特性消失，导致能量分离性能下降。入口压力的增加导致性能的改善和峰值频率幅度的显着提高。此外，分析了在入口压力增加的情况下的能量分离过程和性能。观察到，进动频率的增加赋予较高的能量传递能力，这导致较高的性能。基于这些观察结果确定了大型旋涡的模式和旋涡管的能量分离。另外，进动频率的提高可以提供新颖的概念，基于该概念可以提高涡流管的性能。最后，