Several modelling approaches are presented starting with the classic water hammer through to a combined unsteady friction + viscoelastic approach. This mathematical approach combines the more typical unsteady friction method while introducing additional terms for pipe-wall viscoelasticity. The results of the simulation were compared with experimental data to validate the numerical simulations. Unlike the water hammer or unsteady friction models the viscoelastic approach is capable of accurately predicting transient fluctuations in the wall due to pressure. This is then used to account for the disagreement that is observed between unsteady friction simulations and experimental results through the introduction of the viscoelastic hydraulic transients. Finally several conclusions around viscoelastic damping and the useful effects that this can have on system performance are drawn.

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