[Lettre autographe signée de Giuseppina Verdi adressée à Escudier, Sant'Agata, 3 janvier 1865]

En français

Audit report on Taylor County, Iowa for the year ended June 30, 2009

Audit report on Taylor County, Iowa for the year ended June 30, 2009

Audit report on Taylor County, Iowa for the year ended June 30, 2010

Audit report on Taylor County, Iowa for the year ended June 30, 2010

En 'nordman' i Fredrikshamn : Johannes Holmsen (1865-1941)

Selostus: 'Normanni' Haminassa : Johannes Holmsen 1865-1941

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.