Topological instability of stripes in Hele-Shaw cells. 1. Viscous instability

A. Cebers

Institute of Physics, Latvian Academy of Sciences, Salaspils-1, LV-2169, Latvia

Abstract
It is shown that uniform displacement of liquid stripe in Hele-Shaw cell by other liquid is unstable. By numerical simulations on the basis of the boundary integral equation technique it is illustrated numerically that due to the instability the nonsymmetric stripe deformations develop, which can lead to the formation of narrow necks and rupture of the stripe. Results of the numerical simulation are in qualitative accordance with the predictions of the linear theory. Relevance to the recent experiments on the behaviour of the system of magnetic stripes is indicated and influence of the long-range magnetic forces on the topological instability discussed. Figs 4, Refs. 20.