QU Ningning, CAI Xiaoshu, ZHOU Wu, et al. Experimental measurement of coherent structures of turbulent boundary layer by motion single frame imaging method[J]. CIESC Journal, 2017, (11): 4088-4094.
QU Ningning, CAI Xiaoshu, ZHOU Wu, et al. Experimental measurement of coherent structures of turbulent boundary layer by motion single frame imaging method[J]. CIESC Journal, 2017, (11): 4088-4094.DOI: 10.11949/j.issn.0438-1157.20170469.
Based on the single frame and single exposure imaging (SFSE) method for flow field measurement
the motion single frame and long exposure imaging (MSFLE) method is proposed for measuring the coherent structure of turbulence in the plant turbulent boundary layer. The method is a Lagrangian property measurement technique. The camera moves at substantially the same speed as the migration speed of the coherent structure
and the trajectory of the particle is recorded by the method of long exposure. Experiments were carried out with this method to measure the development of the coherent structure in the turbulent boundary layer. The evolution of the coherent structure with time and space were intuitively recorded. The motion characteristics of the coherent structure are analyzed. The experimental results show that the interaction between the high and low speed streaks can lead to the displacement
merging and dissipation of the hairpin vortex. The existence of stagnation point and strong shear layer is the key to the evolution of coherent structure.