抄録
Flow visualization of the oscillatory flows around a circular cylinder was carried out using tracer particles whose specific gravity was set at about the same as the water's one. The flow field at various phases of the main oscillatory flow was pictured using a motor-driven camera. Velocity vector distribution was obtained from the locuses of the individual particles on a photo-print which indicate the lines on which particles moved during the explosure time. The technique which enables to distinguish the directions of movements of individual particles on a photo-print was employed.
