Dynamics of capillary rise

An overview and detailed analysis of the classical theory of capillarity is presented. A number of known equations of capillary rise dynamics are show n to be different limiting cases of one rather general equation. Some inter nal inconsistencies of the classical equations are pointed out, The role of nonlinear dissipation and flow pattern effects in the front zone of the li quid column and near the capillary entrance is discussed. Numerical simulat ions and experimental data demonstrating some characteristic types of dynam ic behavior predicted by the theory are reported. Special attention is paid to the capillary rise of surfactant solutions. As applied to this special case, the existing theory is substantially elaborated by setting up a close d system of equations describing the surfactant transport and relaxation pr ocesses in the adsorption layer. A simplified relation for the capillary ri se dynamics in the case of strong depletion of the interfacial region is ob tained, which is in qualitative agreement with the experimental behavior. ( C) 2000 Academic Press.