Résumé
The erosion mechanisms driving the particle detachment of a soil under an impinging jet arehere analysed from a micromechanical perspective combining the numerical Discrete Element and LatticeBoltzmann methods (DEM-LBM). Firstly, the local hydrodynamic conditions of both free and impinging jetsare examined and briefly discussed, particularly on the relevance of the superficial irregularities of the granularassembly, which can dominate the local distribution of hydrodynamic variables over the impingementarea. Profiles of both macromechanic and discrete (micromechanic) variables will be put forward. Then, theonset of erosion is reviewed from a topological point of view (locality of first grain motion) on the basis of aparametric study. Finally, the variation of the critical inflow velocity for the initiation of erosion in dependenceon the particle size is also examined and briefly discussed.