THE R-4 5-PROBLEM IN THE DRAINAGE OF DIMPLED THIN LIQUID-FILMS/

A new formula describing the thinning rate of dimpled thin liquid film s is derived. In contrast to the Reynolds law, the predicted rate of d rainage is inversely proportional to the film radius R raised to the p ower of 4/5 and is in excellent agreement with the known experimental results. It is demonstrated that the drainage of small films obeys the Reynolds formula and a criterion for the transition between the two r egimes of thinning is proposed. An estimation of the thickness inhomog eneity in dimpled films is also obtained. (C) 1998 Elsevier Science B. V. All rights reserved.