Nonlinear penetration of liquid drops into radial capillaries

The nonlinear dynamics of the impact and penetration of a liquid droplet in a radial capillary is studied numerically. The radial capillary is formed by two parallel plates at a distance of <f>δg</f>. The top plate has an orifice at its center. A droplet impacting on the orifice-plate partly spreads over the top plate, and the rest penetrates into the capillary gap between the two plates. The rate of spread of the fluid on the orifice plate, <f>ξout</f>, is governed by the contact angle, <f>β</f>, between the liquid and the orifice plate and the droplet initial momentum, whereas the rate of fluid spread inside the capillary gap, <f>ξin</f>, is decided by the contact angles with both plates and the plate gap, <f>δg</f>. [Copyright &y& Elsevier]