Three-dimensional numerical modeling of the movement of the flood mixture in conditions of complex river topography by taking into account the moving river bed

The proposed work reproduces the process of a landslide flow on a complex river relief. The interaction of water and landslide in the form of a porous region is demonstrated using the volume of fluid (VOF) method. For the relationship between phases, a modified mathematical model was proposed to describe non-Newtonian and Newtonian fluids. To reliably simulate a landslide, a non-Newtonian fluid with a density of 2630 kg/m3 was taken as the basis for bottom sediments in the porous area. All numerical simulation results are in good agreement with experimental calculations, which confirms the ability of the developed model to simulate complex waves generated near landslide structures. The results show that the proposed numerical modeling approach can be used to accurately and efficiently estimate the arrival time (26 s) and average velocity of debris flow (26 m/s) during a sudden dam failure for a complex river bed geometry replicating the landscape of the Kargalinka River in Almaty region, Kazakhstan. The main goal of the study is to develop a numerical approach to study floods and inundations caused by dam failures on a real 3D topology. Thus, the numerical modeling used has proven its effectiveness and reliability when used for the 3D problem of breaking a dam in the Karagalinka river bed with complex terrain.