Author(s): Aaron C. Zecchin; Pedro J. Lee

Linked Author(s): Aaron Zecchin

Keywords: Pipeline transients; Unsteady shear stress; Passivity preserving

Abstract: The need for more accurate simulation of transient pipe flow has seen a rising interest in unsteady friction models. Such models capture the dynamic wall shear effects within an accelerating (or decelerating) pipe flow. These models take the form of a convolution operator on the mean axial acceleration of the flow. Given the computational burden of the convolution calculation, computationally efficient approximate methods have been developed. These methods approximate the convolution kernel with a finite series of exponential functions. Such approximations can potentially lead to non-physical models that violate fundamental physical laws. This paper analyses these approximations with respect to the criteria of passivity (the physical models must dissipate energy). From this analysis, a sufficient condition for the strict passivity of the approximations is obtained.

DOI:

Year: 2011