Postbuckling of cylindrical shells conveying viscous flow

Lagrangian nonlinear shell theory was used to describe the elastic deformation of the walls of a collapsible tube brought about by a viscous fluid flowing through the tube. The coupled fluid-solid was discretized using a finite element technique based on the shell equations. Computations of the postbuckling behavior corresponding to an experimental procedure, wherein the volume flux is increased until buckling occurs, were performed. With full fluid-solid coupling, the increased pressure drop in the strongly collapsed part of the tube accelerated the collapse to such an extent that the buckling led to immediate opposite wall contact after the buckling.