Abstract: One of important problems in the field of the environment protection is population safety at accidents on facilities of the chemical industry and power plants connected with processing and storage of liquefied toxic and flammable gases. Such accidents involve the high risk both for the personnel of these facilities and for the population of adjacent regions, as well as cause great economic damage. As a full-scale natural experiment on such facilities is impossible, the mathematical modeling method, which can predict the dynamics of probable accidents and estimate their possible consequences, remains the basic research tool that can be used. Also mathematical modeling allows one to reconstruct events and analyze accidents that have already occurred.
Turbulent flows arising during real emergency emissions have a complex three-dimensional character that essentially complicates their numerical simulation. However, for an operative estimation of the development of emergencies, specific models are needed. Using these models, fast computations of the dynamics of accidents can be conducted on personal computers and their consequences can be estimated. In the development of such models, it is expedient to use simplified two-dimensional problem statements taking into account the features of the considered flows. Propagation of non-reacting heavy gas clouds over a non-uniform surface is described by the two-dimensional model with averaging over the cloud height.
Results of numerical simulation of real accidents with the heavy hydrocarbons cloud spreading over a non-uniform surface and with the toxic modeling emergency situation given by the chlorine propagation cloud in the urban environment are shown.

Brief biography of the speaker:
Andrey A. Kuleshov, Doctor of Sciences in Physics and Mathematics, Main researcher of Keldysh Institute of Applied Mathematics of Russian Academy of Sciences, Professor of National Research Nuclear University ĞMEPhIğ in Obninsk Institute for Nuclear Power, Professor of National Research University ĞMoscow Power Engineering Instituteğ. Graduated from Lomonosov Moscow State University (MSU) Faculty of Computational Mathematics and Cybernetics, obtained Ph.D. at MSU in 1983. Obtained Dr. Sci. in 2005.
Research fields: Numerical methods, Computational fluid dynamics, Mathematical modeling. Has published more than 100 papers. Leader and participant of projects of Russian Foundation for Basic Research, ISTC and Russian Academy of Sciences. Took part in many International Conferences, including WSEAS International Conferences.
His investigations in the field of Mathematical modeling in Environment problems have started in 1984 at Kurchatov Institute of Atomic Energy. Since 1998 he has worked in Keldysh Institute of Applied Mathematics.