Wave propagation in fluids contained in finite-length anisotropic viscoelastic pipes

Wave propagation characteristics are studied of a fluid-filled, finite-leng th anisotropic viscoelastic pipe-a flexible hydraulic hose. An analytical m odel in transfer matrix form is developed for relating the pressure and flo w ripples at hose upstream and downstream. The anisotropic viscoelasticity of the hose wall, the coupled vibration of the hose and the fluid, and the effect of possible longitudinal resonances of the finite-length hose are co nsidered. The static mechanical properties and frequency-dependent mechanic al properties of the hose wall are determined by means of specially designe d static expansion method and optimal searching method separately. Experime ntal confirmation is made over a wide frequency range by using an experimen tal procedure for measuring the transfer matrix parameters. By comparing th e predicted and measured results of the hoses with different lengths, it is shown that the model yields fairly good results in a frequency range of ar ound 0-3 kHz and even may predict the influence of longitudinal resonances of the hose wall on the wave propagation of fluid in the hose. The effectiv eness of the experimental methods and procedure proposed here are also veri fied. (C) 1998 Acoustical Society of America. [S0001-4966(98)00112-X].