Incompressible low-speed-ratio flow in non-uniform distensible tubes

SUMMARY The fluid flow in distensible tubes is analysed by a finite element method based on an uncoupled solution of the equations of wall motion and fluid flow. Special attention is paid to the choice of proper boundary conditions. Computations were made for sinusoidal flow in a distensible uniform tube with the Womersley parameter SI = 5, and a ratio between tube radius and wavelength from O~OOO1 to 0.5. The agreement between the numerical results and Womersley’s analytic solution depends on the speed ratio between fluid and wave velocity, and is fair for speed ratios up to 0.05. The analysis of the flow field in a distensible tube with a local inhomogeneity revealed a marked influence of wave phenomena and wall motion on the velocity profiles.