Numerical evaluation of human sliding instability risk under overtopping flow on a hydrophilic revetment

Hydrophilic revetments serve various pedestrian needs, including walking and wading, but they also confront serious wave overtopping challenges. Pedestrians on these revetments may face instability, falls, or even accidents leading to slipping into the sea due to overtopping flow. This study numerically investigates the hydrodynamic processes of overtopping flow impacting human bodies on a vertical hydrophilic revetment. A human sliding instability model tailored to wave overtopping conditions is developed, analyzing the human instability risks under different orientations (frontal, lateral and oblique), movement postures (stationary, slow walking and brisk walking), and somatotype (children, adults 1 and 2). The findings indicate that pedestrians facing overtopping flow at a 45° angle experience the maximum impact force. While brisk-walking pedestrians generally encounter lower impact forces, the effect of concomitant inertial force doubles their instability risk compared to when stationary. Notably, the instability risk for children is approximately 5.7 times that for adult one when facing wave overtopping. This research can provide a scientific foundation for designing and managing hydrophilic spaces in coastal areas.