Oscillation of Capillary Rise in Eccentric Annuli

The monotonicity and oscillations of the capillary rise in an eccentric cylindrical annulus, are investigated. The second-order nonlinear ordinary differential equation, which governs the rise, requires the HagenPoiseuille velocity distribution across the annulus. We use the special bipolar coordinates system to generate the needed velocity distribution. The results of the proposed study shall bring geometric and material conditions (radii ratio, eccentricity, and Bond and Galileo numbers) under which the rise transforms from being monotone to oscillatory.