Static drop formation on an inclined flat plate

Effect of inclination angle β on static drop formation into air from a hole in an inclined flat plate was studied experimentally and theoretically. In the experiments, water was used as the liquid and Teflon and acrylic resin were used as the solid. In the case of fixed contact line, the experimental relation between maximum drop volume V_max and β agrees well with the theoretical prediction by analysis of the variational problem in which the total potential energy of the system is minimized. An approximated equation for V_max and an experimental equation for residual drop volume V_min are presented. In the case of free contact line, drop formation is affected both by the advancing contact angle and by the receding contact angle. The drop formation course can be simulated roughly by assuming a circular contact line, and the experimental relations between V_max and β are explained by the theory.