抄録
In order to understand the complex flow in a vortex flow meter, water flows around a circular cylinder and a trapezoid cylinder in a circular pipe were observed with the aid of a putting-dye method, in the Reynolds number range from 780 to 19, 000 of the pipe flow. From this visualization experiments, three dimensional characteristics of the flow such as formation and shedding of 3-D vortices, formation of horse-shoe vortices and appearance of 3-D separation regions on the pipe wall, were known.
