The dynamic mechanism of the vortex generation and evolution process in a fully developed turbulent boundary layer with Re₀ = 97–194 is experimentally investigated. In this study, a moving single-frame and long-exposure (MSFLE) imaging method and a moving particle image velocimetry/particle tracing velocimetry (M-PIV/PTV) are designed and implemented for measuring the temporal and spatial evolution of vortex cores in both qualitative and quantitative ways, respectively. On the other hand, the Liutex vector, which is a new mathematical definition and identification of the vortex core proposed by Liu’s group, is first applied in the experiment for the structural visualization and quantitative analysis of the local fluid rotation. The results show that an intuitional process of vortex evolution can be clearly observed by tracking the vortex using MSFLE and verify that the roll-up of the shear layer induced by shear instability is the origin of vortex formation in turbulence. Furthermore, a quantitative investigation in terms of the critical vortex core boundary (size) and its accurate rotation strength is carried out based on the Liutex vector field analysis by M-PIV/PTV. According to statistics of the relation between vortex core size and the rotation strength during the whole process, the physical mechanism of vortex generation and evolution in a turbulent boundary layer of low Reynolds number can be summarized as a four-dominant-state course consisting of the “synchronous linear segment (SL)-absolute enhancement segment (AE)-absolute diffusion segment (AD)-skewing dissipation segment (SD)”.

Re ₀充分发展的湍流边界层中涡旋产生和演化过程的动力学机制= 97–194已通过实验研究。在这项研究中，设计并实现了移动单帧长时间曝光（MSFLE）成像方法和运动粒子图像测速/粒子跟踪测速（M-PIV / PTV）技术，以测量涡旋核的时空演化。分别采用定性和定量方式。另一方面，Liutex向量是由Liu小组提出的对旋涡核的新的数学定义和识别，首先在实验中用于局部流体旋转的结构可视化和定量分析。结果表明，通过使用MSFLE跟踪旋涡，可以清楚地观察到旋涡的直觉过程，并验证了由剪切不稳定性引起的剪切层的卷起是湍流中旋涡形成的起源。此外，基于M-PIV / PTV的Liutex矢量场分析，对临界涡流核心边界（大小）及其精确的旋转强度进行了定量研究。根据整个过程中涡核尺寸与旋转强度之间关系的统计，