Boulder dislodgement and transport by solitary waves: Insights from three-dimensional numerical simulations

The analysis of boulder motion and dislodgement provides important insights into the physics of the causative processes, i.e., whether or not a boulder was moved during a storm or tsunami and the magnitude of the respective event. Previous studies were mainly based on simplified models and threshold considerations. We employ three‐dimensional numerical simulation of the hydrodynamics coupled with rigid body dynamics to study boulder dislodgement and transport by solitary waves. We explore the effects of three important nondimensional parameters on the boulder transport problem, the Froude number Fr, the aspect ratio in logarithmic scale α, and the submergence factor, β. Our results indicate that boulder motion is complex, and small changes in one of the nondimensional parameters result in significantly different behavior during the transport process and the final resting place of boulders. More studies are needed to determine the role of boulders in tsunami and storm hazard assessments. Key Points Better approach is needed to distinguish boulders moved by storms from tsunamis Three‐dimensional simulations are more accurate than simplified approaches Boulder dislodgement is complex and nonlinear. More work is needed