Impulse Response Method for Frequency-Dependent Pipeline Transients

Abstract

An effective numerical method is presented to compute transients in piping systems in which frequency-dependent parameters influence the response. Frequency-dependent friction is utilized as the parameter-of-concern herein, however, the procedure can accommodate other factors such as frequency-dependent wavespeed equally well. The method, a variation in the impulse response method, is developed from the frequency response analysis and incorporates the fast Fourier transform. Examples are included showing the application of the method in computing both classic waterhammer and transients in pipes with frequency-dependent friction. Computed results agree very well with those from the standard method of characteristics and with physical experiments.