Frequency-dependent friction in pipelines*

A comprehensive study of modeling the frequency-dependent friction in a pipeline during pressure transients following a sudden cut-off of the flow is presented. A new method using genetic algorithms (GAs) for parameter identification of the weighting function coefficients of the frequency-dependent friction model is described. The number of weighting terms required in the friction model is obtained. Comparisons between simulation results and experimental data of transient pressure pulsations close to the valve in horizontal upstream and downstream pipelines are carried out respectively. The validity of the parameter identification method for weighting function coefficients and the calculation method for the number of weighting terms in the friction model is confirmed.