TIME-DEPENDENT EQUATIONS GOVERNING THE SHAPE OF A 2-DIMENSIONAL LIQUID CURTAIN .2. EXPERIMENT

In Part I of this paper, two governing equations have been derived tha t describe the shape of a falling liquid sheet (a curtain) subjected t o ambient pressure disturbances. These equations are termed varicose a nd sinuous. The varicose equation governs thickness variations in the curtain, for which the two air-liquid interfaces move exactly out of p hase. The sinuous equation governs the deflection of the curtain centr eline, i.e., the two air-liquid interfaces move in phase such that the local thickness of the liquid is preserved. To the order of the appro ximations used, the theory presented in Part 1 indicates that pressure disturbances invoke a sinuous curtain deflection with no varicose con tribution. In Part 2 of this paper, the sinuous equation is verified b y means of a localised pressure disturbance induced by an electrostati c field. After initiation, the propagation of this disturbance is foll owed and the shape of the air liquid interface is measured using a las er reflection technique. Both the generation and detection of the dist urbance are non-contacting and therefore allow a precise verification of the equation. [S1070-6631(97)02312-X].