Comment on "Selection of the Saffman-Taylor finger width in the absence of surface tension: an exact result"

A Comment on the Letter by Mark Mineev-Weinstein, Phys. Rev. Lett. 80, 2113 (1998). The authors of the Letter offer a Reply.

Nonlinear Saffman-Taylor instability

We show, both theoretically and experimentally, that the interface between two viscous fluids in a Hele-Shaw cell can be nonlinearly unstable before the Saffman-Taylor linear instability point is reached. We identify the family of exact elastica solutions [Nye et al., Eur. J. Phys. 5, 73 (1984)] as the unstable branch of the corresponding subcritical bifurcation which ends up at a topological singularity defined by interface pinchoff. We devise an experimental procedure to prepare arbitrary initial conditions in a Hele-Shaw cell. This is used to test the proposed bifurcation scenario and quantitatively asses its practical relevance.

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The Food Assistance Program provides nutrition assistance to people with low income. Food Assistance can help you buy nutritious foods for a better diet. Produced bye Iowa’s Food Assistance Program, Department of Human Services.

Chef Charles Says..., November 2011

The Food Assistance Program provides nutrition assistance to people with low income. Food Assistance can help you buy nutritious foods for a better diet. Produced bye Iowa’s Food Assistance Program, Department of Human Services.

Chef Charles Says..., December 2011

The Food Assistance Program provides nutrition assistance to people with low income. Food Assistance can help you buy nutritious foods for a better diet. Produced bye Iowa’s Food Assistance Program, Department of Human Services.