Three-dimensional collapse and steady flow in thick-walled flexible tubes

Three-dimensional collapse of and steady flow through finite-length elastic tubes are studied numerically. The Navier-Stokes equations coupled with large, nonlinear deformation of the elastic wall are solved by using the finite-element software, FIDAP. Three-dimensional solid elements are used for the elastic wall, allowing us to specify any wall thickness required. Plane-strain results for the cross-sectional shape of thinner-walled tubes are validated by comparison with published numerical data. Three-dimensional results for flow through finite-thickness tubes are in excellent agreement with published numerical results based on thin-shell elements, and are used to show the effects of varying wall thickness. Finally, the computational predictions are compared with experimental pressure-area relationships for thick-walled tubes. The simulations confirm a previously neglected experimental finding, that the Young wavespeed can be lower between buckling and osculation for thick tubes than for thinner ones.