Lattice Boltzmann method-discrete element method coupling study on the hydrodynamics of waves generated by granular collapse into water

This study investigates the hydrodynamics of tsunami-like waves induced by granular column collapse into water using a coupled lattice Boltzmann-discrete element method. Three-dimensional numerical simulations were carried out to evaluate the effects of column aspect ratio, particle diameter, and water depth on wave evolution and the impact forces exerted on downstream structures. Results show that larger particles enhance wave amplitude and accelerate crest propagation by reducing internal dissipation, whereas smaller particles generate deeper cavities that recover more rapidly. Increased water depth augments hydrostatic pressure, dynamic impulse loading, and reflection velocity. Force analysis further indicates that the downstream wall is subjected to both hydrostatic and dynamic pressures, with peak forces rising by approximately 50% at larger aspect ratios, a = 2.5. Channel-bed loading is primarily controlled by gravity, with pulsations linked to collapse dynamics that diminish as equilibrium is approached. These findings enhance understanding of landslide-induced wave hydrodynamics and their potential impact on downstream defenses.