Abstract. The paper presents results of 3D numerical simulations of shock wave spreading in cityscape area modeled by prismatic bodies placed on a flat plate and inside a closed room. ANSYS Autodyne software is used for the computations. Four different test cases are investi- INTRODUCTIONNowadays, a lot of industrial accidents accompanied by explosions are happening throughout the world. Also, increase in the number of terrorist acts committed by means of explosions is observed. For improving safety of buildings and structures it is necessary to raise their resistance to explosive effects, as well as to be able to predict degree of potential damage upon explosive loads of various intensities [1 -3]. One of the principal goals in designing the structure resistant to explosive effects is to determine the dynamic response of structures to the impact of the blast wave. To this end, the transient pressure loads on the walls of the civil engineering structures are to be determined.The simulation of explosion is highly complicated, involving an explosion causing the shock wave propagation in air and then interaction with a structure. In recent years, many efforts have been devoted to the development of reliable methods and algorithms for a more realistic analysis of structures subjected to blast loading. Blast predictions are most commonly conducted in one of two ways: simplified analytical and engineering methods [4 -6] or sophisticated CFD models [7 -8].The engineering-level techniques permit one to estimate an explosive shock impact only for isolated buildings. The complexity of the building, the presence of nearby structures and the surrounding environment can't be taken into account. To overcome these limitations, various CFD instrumentations are used for blast impact on the civil engineering objects including in-house and commercial software. Advanced computer aid engineering (CAE) software techniques combined with the latest methods of discrete three-dimensional city modeling permits one to simulate and analyze the effects of explosions in urban areas with a precision which previously was not possible [9, 10].In the previous papers by the authors [11,12], the adaptation of LS-DYNA and AUTODYN software was performed for the 3D problem of the blast wave impact on the single prism installed on the flat plate. Comparison of the simulation results to the experimental data [13] has shown that LS-DYNA and AUTODYN allow one to perform numerical modelling of explosive impact on the environment with an acceptable accuracy. The simplified engineering formulas gave a good coincidence with the experimental data only for the gauges situated on the windward surface of the model.In the paper, ANSYS AUTODYN software was tested on the problems of blast wave propagation in the open and closed spaces. The simulation results are compared to the experimental and numerical data [13 -17]. The ability of two numerical schemes [18][19][20] is studied to predict the pressure history in gauges placed on walls of obstacles.

Abstract. In the present paper, the numerical and experimental study of the flows in

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