平面壁上の円錐台まわりの流れおよび渦流出に及ぼすテーパの影響(流体工学,流体機械)

抄録

This paper describes an experimental study of the flow past a tapered circular 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 400mm×400mm×2000mm in size at the Reynolds number 1.29×10^4 and 3.87×10^4. The surface-pressure distribution on tapered cylinder of taper ratio of t=0, 0.05, 0.10, 0.143 (H/D=7) and t=0, 0.385, 0.769, 1.154 (H/D=0.87), and around the tapered cylinder on the ground plane were measured. The drag and lift coefficients were determined by integration of the surface pressure. The vortices of two kinds generated in the flowfield around a tapered cylinder have also been observed by the flow visualization. Consequently it is found that the Karman vortices and arch vortices were shed from the tapered cylinder and circular cone of vertex angle 2α=8°(H/D=7), and from the tapered cyliner and circular cone of vertex angle 2α=60°(H/D=0.87) respectively.