Abstract
The formation process of the slender liquid lump, which is produced in the laminar-turbulent transition process of a radial liquid sheet flow, is clarified. The radial liquid sheet is formed by the release of a radial liquid-film flowing on a disk from the edge of the disk to still air. When the Reynolds number is large, a concentric disturbance wave ('D wave') appeares and grows downstream on free surfaces of the liquid sheet. 'D wave' is caused by the unstable disturbance, which is attributable to the inflectional velocity distribution of the liquid sheet. After the growth of 'D wave', laminar-turbulent transition occurs and slender liquid lumps are formed. Slender liquid lumps disintegrate into drops downstream. The detail observation of the laminar-turbulent transition process reveals that the formation of the slender liquid lumps takes root in three-dimensional deformation of 'D wave'.
