Suppressing van der Waals rupture of thin films by imposed shear flow

It is known that thin viscous films subject to attractive van der Waals forces will rupture in finite time due to a long-wave instability. We have studied the effects of applying a shear stress to the free surface of a film on a substrate, and found that it stabilizes perturbations in the direction of shear flow, thereby retarding rupture, or even suppressing rupture entirely for shear stress above a critical value. Perturbations orthogonal to the shear flow are not stabilized, and therefore a unidirectional shear will not prevent rupture in a three- dimensional viscous film. However, it may be possible to stabilize the film in all directions through the application of a rotating shear stress.