Instability of Free Films with Plateau Borders

A surfactant-free foam of low liquid fraction coarsens by the rupture of the free films separating adjacent gas bubbles. One can find asymptotic solutions for the film and Plateau borders (Brush, L.~N.~\& Davis, S.~H., \emph{J.~Fluid Mech.}, \textbf{534}, 2005, 227-236). Using this time-dependent, flowing, non-planar solution as a basic state, we examine the linearized instability numerically. The numerical method utilizes grid generation to facilitate a finite difference calculation of the linear stability problem.