Numerical analysis of geometrical and mechanical characteristics of the sliding mass influences on impulsive wave generation in dam reservoirs

Impulsive waves caused by landslides into lakes and dam reservoirs strike the shores and dam bodies as large waves. The most important factor in their generation is the transfer of momentum from the mass to the water, which can cause damage. Therefore, understanding the factors influencing this phenomenon is a constant concern for researchers. In this study, the simultaneous effect of the mechanical and geometrical characteristics of the landslide mass was investigated. The investigations were carried out in two parts. First, a laboratory model was used to generate a wave to verify the performance of the numerical Flow-3D model, and then four variables of material, width, thickness, and impact velocity of the mass in wave generation were investigated numerically. The results showed that by increasing the thickness of the mass by 20%, the wavelength increased by about 25%. The volume of the mass was more effective than the width or thickness variables separately, and a mass with a larger volume generated a larger wave. According to the results, increasing the velocity of the mass led to the production of a larger wave, which was related to the material of the mass. With a 14% increase in impact velocity, a 50% increase in wavelength was created in the rigid mass and a 30% increase in the porous mass, which showed that in the rigid mass, the effect of velocity on the wave magnitude was greater.