3D NUMERICAL MODEL FOR TERRITORIAL RISK ASSESMENT AFTER TERRORIST ACT

Purpose. A goal of the work is development of 3D numerical model for a territorial risk assessment in a case of a terrorist attack with usage of a chemical agent. Methodology. To describe the process of chemical agent dispersion in the atmosphere, emitted in a case of a terrorist attack, the equation of mass transfer of an admixture in atmospheric air is used. The equation takes into account a velocity of the wind flow, atmospheric diffusion, an intensity of chemical agent emission, a buildings presence near a place of a chemically hazardous substance release. For numerical integration of the modeling equation, a finite difference method is used. A feature of the developed numerical model is possibility of a territorial risk assessment in a case of a terrorist attack under different weather conditions and a buildings presence. For calculation of wind flow velocity field in a case of building presence 3D equation for potential of velocity is used. Findings. The specialized numerical model and software package which can be used for a territorial risk assessment, both in a case of terrorist attacks with usage of chemical agents, and in a case of extreme situations at chemically hazardous facilities and transport are developed. The method can be implemented on small and medium-powered computers, which allows it to be widely used for solving this class of problems. The results of a computational experiment are presented that allow estimating possibilities of the proposed method for assessing a territorial risk in a case of a terrorist attack with usage of chemical agent. Originality. An effective method of a territorial risk assessment in a case of a terrorist attack with usage of a chemically hazardous substance is proposed. The method can be used to assess a territorial risk in an urban environment, which allows to obtain adequate data about possible affected areas. The method is based on numerical integration of the fundamental mass transfer equation, which expresses the law of conservation of mass in a liquid medium. Practical value. The proposed method for a territorial risk assessment in a case of a terrorist attack with usage of a chemical agent can be used to calculate the affected areas near administrative buildings, centers and other socially significant facilities.