Numerical investigation of scour by incompressible SPH coupled with coarse-grained DEM

Abstract Scour is one of the most characteristic interactions between fluid and soil, and it can cause fatal structural or natural damage. In this study, Incompressible Smoothed Particle Hydrodynamics (ISPH) was used to overcome the drawbacks of FVM (Finite Volume Method) and WCSPH (Weakly-Compressible Smoothed Particles Hydrodynamics) as a fluid model. The coarse-grained Discrete Element Method (CGDEM) was employed to simulate the soil particles and reduce computational time by employing larger particle sizes than the experiments. ISPH and CGDEM were coupled by using the fluid porosity of each particle to compute interactions between fluid and solid particles. Three scour simulations based on the laboratory experiments were conducted and validated by the experiment results, and the final profiles of water and soil showed good agreements in the scour depth and length. Furthermore, the CGDEM reduced the computational time by more than 38.7 times compared to the simulations with the original experiment particle sizes. Thus, the ISPH-CGDEM in this paper enhanced the applicability of scouring simulation to large-scale and natural environments.