Modelling transient pipe flow with cavitation and frequency dependent friction. Part I. Cavitation models

Abstract

The paper presents four key mathematical models of transient cavitating pipe flow, i.e. column separation model ([i]Column Separation Model[/i] — CSM), gas cavitation model ([i]Gas Column Separation Model[/i] — CSMG), Adamkowski model (Adamkowski’s Column Separation Model — CSM) and bubbly cavitation model (Bubble Cavitation Model — BCM). In the all investigated models, frequency-dependent frictional losses were taken into account. The equations describing all models have been solved using the method of characteristics. In this work, the wall shear stress (defined as an effect of unsteady fluid friction) is presented as a sum of quasi-steady and unsteady components. The unsteady component of the wall shear stress is modelled as an convolution of local fluid acceleration and a weighting function[i] w(t)[/i].[b]Keywords[/b]: numerical fluid mechanics, transient flow, cavitation, frequency-dependent friction losses, pipeline, waterhammer

Keywords

• numerical fluid mechanics
• transient flow
• cavitation
• frequency-dependent friction losses
• pipeline
• waterhammer