Multiscale Smoothed Particle Hydrodynamics based on a domain-decomposition strategy

A multi-resolution algorithm for weakly-compressible Smoothed Particle Hydrodynamics is hereby proposed. The approach chosen is based on a domain decomposition to subdivide the computational domain into regions with different resolutions. Each sub-problem is closed by appropriate Dirichlet boundary conditions that are enforced via buffer regions, populated by particles whose physical quantities are obtained by means of an interpolation over adjacent sub-domains. The algorithm has been implemented into the DualSPHysics open-source code and it has been tested and validated through a series of different study cases. The capability of the numerical scheme to simulate multiscale fluid flow has been demonstrated by solving the flow past a cylinder for a Reynolds number of 9,500 and a ratio between the largest and smallest particle size equal to 2⁸. Furthermore, the proposed SPH multi-resolution algorithm can also be used for flow around moving objects, such as an oscillating cylinder in cross-flow, and free-surface flow, such as the simulation of a triangular wedge impacting on the free surface of a quiescent liquid.