竖缝式鱼道中安装和移除圆柱体的2D非稳定流动实验研究
Vertical slot fish passes have been applied as a solution to mitigate fish migration problems in running waters, for overtwo decades. They are commonly used to enable target fish to ascend through obstacles in rivers. However, smallspecies are rarely considered in such fishways, of which the performance for small fish still remains unknown. Thisexperiment was to study the turbulence structure in a vertical slot fish pass concerning two different pool length/widthratios of 9 and 6.67 as well as the effect of installing a cylinder behind the slot in affecting the characteristics ofinstationary flow. Cylinders are considered an effective solution to modify the flow structure and to reduce velocity andturbulent energy in order to adapt the flow for the passage of small fish species. Flow visualization and particle imagevelocimetry were used to study the characteristics of mean flow and turbulence and particular emphasis on the unsteadyflow. The results show that flow patterns consist of a water jet and one or two recirculation zones depending on thelength/width ratio of the pool. The direction of the jet was strongly affected by the vertical cylinders. The frequenciesand spatio-temporal evolutions of the main jet beats were analyzed. Combining with the previous studies of fishmigration experiments, the results provide hydraulic evidence on the biological performance.