Fluid-solid interaction is a complex phenomenon commonly encountered in process engineering, biological engineering, or geotechnical engineering. For granular materials, the displacement of the grain system due to the hydrodynamic forces impacts the velocity field of the fluid and vice versa. To predict the fluid-solid interaction, numerical simulations are commonly used that include traditional finite-volume computational fluid dynamics (CFD), or immersed boundary CFD to model granular-fluid coupled systems. Alternative to mesh-based CFD methods, meshless Lagrangian methods (MLMs) such as Smooth Particle Hydrodynamic (SPH) have the advantage to avoid remeshing for the Dynamic fluid domain. In a previous study, a coupling strategy has been developed and validated for the under-resolved solver coupled with Discrete Element Method (DEM) for the granular phase. This development has been integrated into new MLMs-DEM GPU (Graphic Process Unit) solver. This paper validates the DEM-MLM solver to erosion dynamics.