Experiments on the stability of a liquid bridge in an axial electric field

Abstract

The behavior of a neutrally buoyant liquid bridge was studied in the presence of axial electric fields. Silicone oil and a castor-oil–eugenol mixture were used to form cylinders with slenderness ratios larger than π with strong, axial, dc electric fields. Below a certain field strength, a smooth transition to an axisymmetric, vaselike shape occurred. Circulation patterns were observed in these bridges. At lower field strengths, the bridge shape was more deformed and, at a well-defined field, pinch-off occurred. With ac fields, the field strength required to stabilize the bridge was higher and the collapse of the cylinder was much sharper. Upon interchanging the fluids, a steady axial field was found to destabilize cylinders with slenderness ratios less than 3. This behavior is consistent with that anticipated if the fluids behave as leaky dielectrics but not if they act as perfect dielectrics.

Formation of Liquid Columns on Liquid–Liquid Interfaces under Applied Electric Fields

“…Saville (17) analyzed the stability of a fluid cylinder in longitudinal electric fields by using a leaky dielectric model in which the viscous effects were considered to account for the motion and deformation of the cylindrical interface. More work has recently been done on dielectric liquid bridges formed in axial electric fields with interest in applications under small gravity forces, e.g., in space (18)(19)(20)(21)(22). Both direct-current (DC) and alternating-current electric fields were employed in these investigations and the liquid bridges were anchored on two parallel-plate electrodes.…”

Liquid-Column Sustainment Driven by Acoustic Wave Guiding

“…Since the pioneering attempts to stabilize liquid columns using a static axial electric field by Raco [7] and Taylor [8], several passive [9][10][11] and active [12][13][14] strategies have been implemented in order to push further the onset of the RP instability. Nevertheless, none of the recently developed stabilization techniques based on the application of an external field-be it electric [9,10,[13][14][15] or acoustic [11,12]-succeeded in stabilizing columns made of simple liquids of aspect ratios larger than 5.2.…”

“…Nevertheless, none of the recently developed stabilization techniques based on the application of an external field-be it electric [9,10,[13][14][15] or acoustic [11,12]-succeeded in stabilizing columns made of simple liquids of aspect ratios larger than 5.2. However, the maximum aspect ratio à max attainable using passive feedback theoretically increases with the field intensity and is thus a priori not limited.…”

Stability of Magnetically Levitated Liquid Bridges of Arbitrary Volume Subjected to Axial and Lateral Gravity

“…It has been shown both experimentally and theoretically that the presence of axial gravity makes a cylindrical bridge unstable at ⌳ Ͻ (6). In consequence, several stabilization techniques have been developed to push the slenderness ratio beyond these limits (7,8). Theoretical predictions of stability have been made for both axisymmetric bridges subjected to axial gravity, where the gravitational field is along the axis of the liquid column (9 -11), and bridges subjected to lateral gravity, where the gravitational field is perpendicular to the axis of the column (12,13).…”