A novel SPH-SWEs approach for modeling subcritical and supercritical flows at open channel junctions

In the study, a Lagrangian particle method, smoothed particle hydrodynamics (SPH), is attempted to solve the one-dimensional shallow water equations (1D-SWEs) for modeling subcritical and supercritical flows at open channel junctions. SPH-SWEs is so far only limited in the applications of single channel flows. To extend SPH-SWEs to channel junction flows, a novel approach, which considers the internal boundary conditions at junctions in the numerical formulation, is proposed to investigate 1D hydrodynamic behavior of subcritical and supercritical flows at open channel junctions. The Shabayek and Rice junction models derived from the mass and momentum conservation at junctions are adopted to respectively specify the internal boundary conditions in subcritical and supercritical flows. The newly proposed approach is verified with five benchmark study cases, including steady and unsteady, subcritical and supercritical flows in channel junction systems. The numerical convergence and accuracy of the proposed approach are examined and discussed. It is concluded that the proposed SPH-SWEs approach can accurately handle various subcritical and supercritical flow conditions in channel junctions, and can provide an alternative to investigate practical junction flows in open channels.