Numerical Simulation of Turbulent Pipe Flow for Water Hammer

A numerical model of turbulent transient flow is used to study the dynamics of turbulence during different periods of water hammer in a polymeric pipe. The governing equations of the transient flow are solved by using the finite difference (FD) method, and the effects of viscoelasticity are modeled by means of a two-dimensional (2D) Kelvin-Voigt model. The experimental data with the Ghidaoui parameter P in the order of one are chosen in which the generated shear wave propagates toward the center of the pipe, while the pressure wave passes the length of the pipe. By studying the turbulence shear force during different times, it is shown that the turbulence structure changes considerably in the first cycle of water hammer. In the accelerated phases, the dominant feature is the creation of a shear wave near the wall, and in the decelerated phases the dominant feature is the propagation of the shear wave created in the accelerated phase.