Efficient Modeling of the Relevant Effects for Water Hammer Calculation

The essential features for an adequate simulation of water hammer effects are incorporated in the one-dimensional fluiddynamic code ROLAST. This code was developed for the calculation of transient load cases in piping networks, including active and passive components like pumps, valves, check valves, vessels, and allowing for various boundary and initial conditions. The essential models for water hammer treatment are described like condensation, air bubble behaviour and venting, and especially their adaptation to the 1D flow formulation. Examples of validation are given. The role of dissolved air is discussed. The effects of dynamic friction and coupling with the structural analysis on a realistic damping behavior are explained. The code allows the calculation of realistic water hammer loads on the system by considering the reaction of components like check valves at the some time.