Modified dynamic boundary conditions (mDBC) for general-purpose smoothed particle hydrodynamics (SPH): application to tank sloshing, dam break and fish pass problems

Abstract Dynamic boundary conditions (DBC) for solid surfaces are standard in the weakly compressible smoothed particle hydrodynamics (SPH) code DualSPHysics. A stationary is simply represented by fixed particles with pressure from equation of state. Boundaries easy to set up and computations relatively stable efficient, providing robust numerical simulation complex geometries. However, a small unphysical gap between fluid boundaries can form, decreasing accuracy pressures measured on boundary. method presented where density obtained ghost positions within domain linear extrapolation. With this approach, reduced still water converge hydrostatic, including case bed sharp corner. The violent free-surface cases sloshing tank dam break impact an obstacle show directly close agreement experiments. 3-D flow fish pass, baffles divert flow, simulated showing levels weirs open gates closed, but less closed. This indicates suitable rapidly varying flows, development turbulent flows necessary. modified dynamic condition (mDBC) available DualSPHysics run CPUs or GPUs.