Transient Friction in Pressurized Pipes. II: Two-Coefficient Instantaneous Acceleration–Based Model

Abstract

Thegoal in the field of modeling of hydraulic transients isa comprehensive model for pipe networks which is computationally fastand accurate. The fastest models are the one-dimensional (1D) modelswhich use Instantaneous Acceleration Based (IAB) properties, but unfortunately thesemodels are not as accurate as the more demanding 1DConvolution Based (CB) models or quasi two-dimensional models. Focusing ona single pipe, this paper is investigating the fundamental behaviorof the much more accurate 1D CB model in orderto find two coefficients for use with the two-coefficient formulationof the much used Modified IAB (MIAB) model for acomplete closing of a downstream valve. Two coefficients are foundwhich are based on the weighting function used in theCB model, and these coefficients vary along the pipe length.Simulations are compared with two experimental results from test performedat University of Adelaide, Australia, 1995. The experimental results arefor different initial Reynolds numbers of approx. 2000 and 5800.The results show very good agreement between simulations and experiments.The improvement of the MIAB model is not general, forthe time being only complete closure of a downstream valvein a single pipeline at low Reynolds numbers has beeninvestigated. ©2010 ASCE