平面壁上の有限長円柱を過ぎる流れ

抄録

This paper describes an experimental study of the changes of vortices formation and turbulent wake from a circular cylinder with the slenderness of cylinder, placed on a ground plane. The experiment was carried out in an N. P. L. blow down type wind-tunnel having a working section of 500mm×500mm×2, 000mm in size at the Reynolds number 2.5×10⁴ to 4.7×10⁴. The surface-pressure distributions on the circular cylinder were measured and the drag coefficient was determined from them. The vortices of two kinds generated in the flow-field around a circular cylinder have also been observed and the velocity defects and turbulent intensities in the turbulent wake behind a circular cylinder were measured. Consequently, it is found that the flow pattern changes rapidly from H/D=4, while the shedding vortices change from arch type to Karman type.