Coupled computational fluid dynamics-discrete element method for simulating the interactions between ship-induced waves and riprap on restricted waterway banks

Abstract

In inland waterways, waves generated by passing boats cause the movement of riprap used for bank protection and stabilization. Previous studies have mainly concerned the natural channel erosion problem caused by wind-generated waves and neglected the research and findings on shipping behavior. This work presents a coupling of the computational fluid dynamics model and the discrete element method. The aim is to first study the interactions between ship waves in the confined channel and the movements of the riprap of the banks and shorelines and second to analyze the stability of these armourstones under the actions of various ship velocities and draught depths. These varying conditions exert influence on the ship-induced waves, the crucial point being the drawdown amplitude, and consequently create more intense flow behavior in the near-shore region, which results in instability and destruction of the overall structure of the armor protection layer. The higher ship velocity and the larger draught depth lead to the aggravation of instability processes of the blocs composing the protective layer. There is a critical phenomenon in the influence mechanism of vessel velocity, whereas the variation process induced by draught depth is relatively linear. In addition, the stability of the blocs also depends on their shapes, sizes, and the initial positions within the protective layer. This study could contribute to the high-quality development of inland navigation.