112 回転物上のタフト角度におよぼす遠心力の影響

抄録

Tuft angles on rotating bodies were investigated. On rotating bodies, not only the aerodynamic forces but also the centrifugal forces act on tufts. Thus, the tufts do not indicate the flow direction on the rotating bodies. First, an experiment for tufts' behavior on a rotating disk were performed. Needles were stood at the disk surface with different distances from the rotation center. Nylon mono-fiber tufts, that had 25.4mm length and 0.06mm crosssectional diameter, were attached at the points of the needles. The disk were rotated with several different speeds in the air at rest. Pictures of the disk were taken, and then, the angles of the tufts were measured. Secondly, the analysis taken account of the aerodynamic and centrifugal forces for the tufts was also conducted. A comparison of the experimental and analytical results showed good agreement. Lastly, the analysis was extended to predict the tufts angles on the rotating disk in a uniform flow. This condition is similar to the wheels of automobiles' tiers running at a constant speed.