The Radial Flow of a Thin Liquid Film : 1st Report, Laminar-Turbulent Transition

抄録

This paper describes an experimental study of the laminar-turbulent transition in the radial flow of a thin liquid film on horizontal plane. The film flow was obtained by a water discharge from the thin cylindrical opening formed by a circular nozzle and a flat glass plate. The transition mechanism could be clearly observed in a visual observation using a stroboscope, since a turbulent motion in the thin layer of water disturbed the water surface. A sequence of experiments revealed the existence of a critical discharge Reynolds number Re_{t, cr}, based on the equivalent length of opening, above which the transition takes place. The relation between Re and the dimensionless radius r_t^* of the point of transition and the relation between r_t^* and the local Reynolds number Rer based on the film thickness at r_t are established.