Unique shapes of liquid bells as a function of flow parameters: A brief overview and some new results

• Parametric study on liquid bells is conducted.
• Dependence of bell geometry on various factors is studied.
• Gravity, viscosity and surface tension of the liquid affect bell shape.
• Diameter and velocity of the liquid jet affect bell geometry.
• Unique shapes of liquid bell are observed.

The shape of liquid bells formed by thin liquid sheets due to the impingement of jets onto disc shaped objects depends on a large number of parameters. These parameters include physical properties of the liquid like viscosity and surface tension, gravitational acceleration, jet velocity as well as the diameters of the liquid jet and the target disc. In this work the variation of the shape of a liquid bell due to the effect of the above parameters has been investigated based on the governing equations of the bell. It has been observed that for a given impactor diameter a smaller jet diameter results in more symmetrical shapes. Further, the symmetry of the liquid bells increases as g is reduced. Reduction of surface tension has a dramatic effect on bell shapes. Primarily, the maximum radius and length of the bells increase with decreasing surface tension. For a combination of low surface tension with a non-zero pressure difference across the bell surface, unique shapes are seen to appear. Experiments conducted also confirm the bell shapes predicted by the analysis.