Dam-Break Flow on Mobile Bed Through an Idealized City: Numerical Study

摘要

Abstract This paper presents a numerical simulation of a three-phase flow (water, air, and mud) formed during a dam break. For the connection between all phases, the mathematical model was modified to take into account the non-Newtonian and Newtonian fluids. The equations in the mathematical model are discretized by the finite volume method and the relationship between all phases is achieved using the volume of fluid (VOF) method. Modified Navier–Stokes equations for accounting for non-Newtonian and Newtonian fluids are solved by the Pressure-Implicit with Splitting of Operators (PISO) numerical algorithm. To validate the mathematical model and numerical algorithm, the paper demonstrates a comparative analysis of the results with the laboratory experiment. The model tested in this way has confirmed its reliability, accuracy and reasonableness. Additionally, a three-dimensional numerical simulation of the water flow movement in combination with a sedimentary layer in a narrowing channel was considered. A rough estimate of the mud flow behavior in relation to the urbanized area located at the end of the channel is given. When analyzing the numerical results, it can be concluded that an increase in the height of the mud layer leads to a deceleration of the moving flow, which can subsequently be used for the timely evacuation of the population. It should be noticed that the analysis of the comparative graphs showed the deceleration of the water flow by more than 0.2?s for a moving layer depth of 0.025?m and when using a mixed arrangement of the sediment. And also from the obtained results, we can note at least two times decrease in the maximum pressure value that in the presence of sediments.