Characteristics of the Flow around Four Circular Cylinders Arranged in Line

An experimental investigation was carried out on the characteristics of the flow around four circular cylinders arranged in line. concerning the behavior of the shear layers separated from the first cylinder to the downstream ones, the flow patterns were classified according to the longitudinal spacing between the axes of the cylinders and Reynolds numbers. Flow characteristics of these patterns were elucidated. Especially, the Reynolds numbers corresponding to the reattachment of the shear layers onto the second cylinder, were obtained. The flow characteristics around the downstream cylinders changed drastically in this transition region. Thereby, a bistable flow and a hysterisis phenomenon emerged.