Laminar-Turbulent Transition in a Free Liquid Film Flow and its Application to the Atomization

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1. The laminar-turbulent transition in the radial flow of a free liquid film is studied experimentally and theoretically. The flow is generated by making a thin radial liquid film along a horizontally placed circular disk and letting it flow out into the atmosphere. The transition mechanism is observed using a stroboscope. The velocity distributions in a thin free liquid film having a thickness of about 0.2 mm are measured by LDV. The phenomena of the transition is investigated by means of the linear stability theory. As a result, the transition is caused on the nonuniformity of the vorticity distribution inside the liquid film. 2. The laminar-turbulent transition in the radial liquid film flow on a rotating disk is studied experimentally. The flow is generated by letting water discharge from a cylindrical opening between a horizontally placed rotating disk and a circular nozzle into the atmosphere along the upper surface of the disk. The high speed photographes of the process of the transition show that, while the rotation of disk suppresses the transition as long as the circumferencial velocity is relatively small to the radial velocity, it promotes the transition when the circumferencial velocity becomes large.