Particle method of characteristics (PMOC) for unsteady pipe flow

Abstract

A novel particle method of characteristics (PMOC) to simulate unsteady pipe flows is introduced and validated in the present study. Contrary to the conventional method of characteristics (MOC), the present formulation is built by reallocating the computational nodes along the characteristic lines. Both the right- and left-running characteristics are accurately traced and imitated with their associated computational particles. The annoying numerical inconveniences in the fixed-grid arrangement due to incompatible Courant–Friedrichs–Lewy (CFL) condition by repeating solution interpolations is effectively eliminated. Special particles with dual states satisfying the Rankine–Hugoniot relations are deliberately imposed to emulate the shock structure. Efficacy of this formulation is verified by solving some benchmark problems with significant transient effects in pipe flows. Computational results of piezometric head and flow velocity are meticulously compared with available analytical solutions. It is concluded that the proposed PMOC will be a useful tool to replicate transient phenomena in pipe flows.