**6. Conclusions**

**Figure 13.** Three-dimensional surface of the Andijan (left) and Papan (right) reservoirs areas.

water flow, and the blue corresponds to air flow (there is no water flow in blue regions). It is seen in **Figure 14** that the leading front of water flow reaches during 240 s the lower boundary of the computational region passing a distance of about 6000 m, covers the most part of the

The computational field for the Papan reservoir has the sizes 5000 × 5000 × 1300 m (see

The total computing time in the case of the 50 × 60 × 30 grid amounts to about 5 h. As is seen in **Figure 15**, after the moment of time *t* ≈ 200 s there forms a reverse flow (**Figure 15d**

**Figure 14.** Flow pattern for the Andijan reservoir.

area located downstream.

**Figure 15**).

70 Dam Engineering

The results of the mathematical modeling of complex hydrodynamic phenomena on the basis of unsteady three-dimensional Navier-Stokes equations describing the dynamics of a gas-liquid mixture with free boundary have been presented. The adequacy of the employed model has been verified by the example of the classical problems of computational fluid dynamics. Special attention has been paid to the accuracy of the computation of the water flow level and the gas-liquid flow pressure on the reservoir walls. The efficiency of the employed technology has been illustrated by the example of modeling the breaks of the dams of the Andijan (Uzbekistan) and Papan (near the Osh town, Kyrgyzstan) reservoirs. The developed technology is universal and can be used for the flood modeling for a real relief. It is shown that the relief features are a substantial factor.
