Modeling and analysis of water-hammer in coaxial pipes

TL;DR

This paper models water-hammer phenomena in coaxial pipes, analyzing wave propagation, pressure, and strains in both isotropic and anisotropic pipes, validated by experimental data.

Contribution

It extends previous single-pipe analysis to coaxial systems with anisotropic composite pipes, providing detailed wave and strain predictions based on fiber winding angles.

Findings

Multiple wave speeds observed in simulations

Wave and pressure predictions match experimental data

Fiber winding angle influences wave behavior

Abstract

The fluid-structure interaction is studied for a system composed of two coaxial pipes in an annular geometry, for both homogeneous isotropic metal pipes and fiber-reinforced (anisotropic) pipes. Multiple waves, traveling at different speeds and amplitudes, result when a projectile impacts on the water filling the annular space between the pipes. In the case of carbon fiber-reinforced plastic thin pipes we compute the wavespeeds, the fluid pressure and mechanical strains as functions of the fiber winding angle. This generalizes the single-pipe analysis of J. H. You, and K. Inaba, Fluid-structure interaction in water-filled pipes of anisotropic composite materials, J. Fl. Str. 36 (2013). Comparison with a set of experimental measurements seems to validate our models and predictions.