High Speed and Accurate Computing Method of Frequency-Dependent Friction in Laminar Pipe Flow for Characteristics Method

Abstract

An accurate and efficient approximation is developed for simulating frequency-dependent friction in transient laminar pipe flow in the method of characteristics. This method consists of approximating exact W. Zielke's weighting function as a sum of impulse responses of first order lag systems. Simulation using the method brings about much less computer storage and computation time than the use of the exact expression without the error due to the approximation. Calculated results for a test system are compared with the W. Zielke's model so show that by this new method waterhammer phenomena in viscous fluid can be calculated precisely with less computation time.