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

Wave propagation characteristics are studied of a fluid-filled, finite-length anisotropic viscoelastic pipe—a flexible hydraulic hose. An analytical model in transfer matrix form is developed for relating the pressure and flow 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 considered. The static mechanical properties and frequency-dependent mechanical properties of the hose wall are determined by means of specially designed static expansion method and optimal searching method separately. Experimental confirmation is made over a wide frequency range by using an experimental procedure for measuring the transfer matrix parameters. By comparing the 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 around 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 effectiveness of the experimental methods and procedure proposed here are also verified.