Stability of a dome-shape liquid film for conditions when it flows around a plate

Abstract

The experimental research of hydrodynamic stability of a dome-shape film of liquid for the conditions, when it flows around a thin plate has been carried out. Experiments have been executed for a case of Savart "water bell". An axisymmetrical film has been formed by the impact of a liquid jet with the width of 10 mm on a solid disc with the diameter of 14.5 mm. The width of the thin plate, streamlined by a dome-shape water film, was varied from 0.05 to 3.5 mm. The wide side of the plate was located at two angles relative to the direction of the flow velocity vector in a film: along and across, at various distances from the disc. Stability of the "water bell" surface has been considered and general stability criterion showing its sensitivity to the angle of plate orientation has been derived. The critical Weber number, above which the discontinuity of bell surface appears, and threshold value of the Weber number, below which it coalescences, have been defined. It was shown, that the critical and threshold Weber numbers depend on the Reynolds number.