Impulse waves generated by high-Froude-number subaerial landslides in reservoir areas

To explore the formation mechanism and near-field characteristics of impulse waves generated by high-Froude-number subaerial landslides, this study conducts an experimental investigation using a large-scale three-dimensional physical model based on a real-world prototype. The results show that impulse waves propagate radially in the near field, forming multiple distinct wave trains. Among them, the amplitudes of the first two wave trains are substantially greater than those of the subsequent ones. The leading wave consistently manifests as a crest significantly higher than its trough, indicating a strongly nonlinear wave field. In over 70% of the experimental cases, the crest amplitude of the first wave train exceeds that of the second. A clear power-law relationship is observed between the relative wave height and the relative crest amplitude of the primary wave. Based on dimensionless analysis, a new semiempirical prediction formula for the maximum amplitude of the first impulse wave is developed. This formula demonstrates superior predictive accuracy, with errors predominantly below 5%, outperforming several established empirical formulas. Parametric sensitivity analysis indicates that the landslide sliding velocity exerts the most significant influence on the maximum wave amplitude, followed by the water-entry volume, while the initial water depth has a comparatively minor effect. These findings provide a reliable reference for hazard assessment and risk mitigation strategies for reservoirs in mountainous regions.