Summary
In this paper, the dynamics of pipes conveying pulsating fluid are investigated. The fluid flow velocity inside the simply supported pipe is assumed to be small and varying harmonically with a frequency Ω. The linear equations of motion are examined using multiple time-scales perturbation methods. The pipe structure is modelled as a beam-like, as a stretched beam-like and as a string-like problem. The respective partial differential equations governing the dynamics of the system are studied leading to infinite-dimensional systems of ordinary differential equations. When the fluid pulsation frequency Ω is equal to a natural frequency, the sum of two natural frequencies, or the difference of two natural frequencies, the pipe system is observed to exhibit complicated dynamical behaviour. Due to excitations of higher-order modes and internal resonances, it has been shown that applying the widely used Galerkin truncation method can lead to incorrect results.
