Active electrostatic stabilization of liquid bridges in low gravity

Abstract

In experiments performed aboard NASA's low-gravity KC-135 aircraft, it was found that rapid active control of radial electrostatic stresses can be used to suppress the growth of the (2,0) mode on capillary bridges in air. This mode naturally becomes unstable on a cylindrical bridge when the length exceeds the Rayleigh–Plateau (RP) limit. Capillary bridges having a small amount of electrical conductivity were deployed with a ring electrode concentric with each end of the bridge. A signal produced by optically sensing the shape of the bridge was used to control the electrode potentials so as to counteract the growth of the (2,0) mode. Occasionally the uncontrolled growth of the (3,0) mode was observed when the length far exceeded the RP limit. Rapid breakup from the growth of the (2,0) mode on long bridges was confirmed following deactivation of the control.