CFD technology for 3D simulation of large-scale hydrodynamic events and disasters

In this paper we discuss the basic components of the computational technology for the simulation of complex hydrodynamic events, such as a break of a dam, a wave pileup, a landslide, or a mud flow. The technology uses three-dimensional equations of fluid dynamics with free boundaries. The mathematical model is based on the Navier-Stokes equations with nonlinear defining relations between the stress tensor and the rate of strain tensor. The assignment of a particular defining relation allows one to simulate both Newtonian flows (break of a dam, wave pileup), and non-Newtonian ones (landslide, mud flow, snow avalanche, flood of lava). The numerical model developed in the paper uses the method of the grid level set function for calculation of a free surface flow evolution and adaptively reconstructed three-dimensional grids of the octree type for discretization of the flow equations. The predictive accuracy of this technology is demonstrated in the paper by comparing the results of certain numerical calculations with physical experiments; the efficiency of the technology is illustrated by simulation of the break of a dam and a mud flow using the actual 3D topology of the area around the Sayano-Shushenskaya dam.