Contact line instability of a constant volume flow

J. M. GOMBA; J. DIEZ; R. GRATTON; A. G. GONZÁLEZ; L. KONDIC

Paris, Francia

Simposio; 7 th European Coating Symposium - Recent Advances in Coating, Drying and Dynamical Wetting; 2007

We numerically study the linear stability of the contact line for a constant volume (CV) of fluid spreading down an incline, as an example of a flow with no  translational invariance. Within the lubrication approximation, we use a precursor film to relax the contact line  singularity. Unlike the constant flux case, the base flow of the present situation depends on time. Consequently, we simultaneously solve the time evolution of the base flow  and perturbations by means of a finite difference numerical code which uses an integral method developed here.  The main difficulty to solve this case lies in the fact that  the base state is time-dependent, as it occurs in most of   the flows found in applications. The analysis presented  here avoids the use of simplified conditions, such as theimposition of a constant fluid thickness in the bulk region -constant flux (CF) flow-, and aims to give a more accurate description of the instability in realistic flow.