Matthew Beauregard

Analysis of Elastic Filaments Conveying a Fluid and a Numerical Study: Weakly Nonlinear Analysis of Elastic Filaments Conveying a Fluid and Numerical Approximations to the Static Kirhhoff Equations Matthew Beauregard

Two problems in the study of elastic filaments are considered. First, a reliable numerical algorithm is developed that can determine the shape of a static elastic rod under a variety of conditions. In this algorithm the governing equations are written entirely in terms of local coordinates and are discretized using finite differences. The algorithm is seen to have significant advantages. In the second problem a model is presented describing the dynamics of an elastic tube conveying a fluid. A study into the effect of the fluid on the twist-to- writhe instability is given. A linear stability analysis demonstrates that for an infinite rod the twist-to-writhe threshold is lowered by the presence of a fluid flow. It is shown that for finite length tubes the bifurcation threshold depends delicately on the length of the tube and that it can be either raised or lowered relative to the fluid-free case.