抄録
Wake flow behind a circular cylinder with a flat step is visualized by dye-injection method and measured by hot wire anemometer. Vorticies of wake flow with different shedding frequencies change its relative locations with time. I-type connection, phase change, Y-type connection and disjunction repeat periodically. RMS values of fluctuating velocities have a maximum at I-type connection and a minimum at Y-type connection.
