市街地火災に於ける風下側の熱気流性状の予測に関する研究

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There are several models that have been developed for simulating the spread of fire in cities. The earliest one of these models expressed the speed of fire spread as a function of wind velocity and average building-to-building distance, which was constructed statistically based on the investigations of urban fire incidents in the past. Another took into account fire resistance performance of houses. All of these models are basically regarded as empirical models. However, the conditions of urban areas have significantly changed since the model was first established. It is doubtful that the fire damage in contemporary cities could rationally be assessed through the use of these models. Here we tried to develop a system for fire forecasting and damage prediction based on the Physical Model. This new model should be able to account for the interaction between burning houses and the wind flow over a city, because strong winds are known to be a major cause to enlarge the damaged area. Our experimental study using simultaneous measuring of wind speed and temperature seeks to understand the characteristics of the high temperature field behind a fire in the turbulent boundary layer and to obtain the verification data for the numerical simulations. We also reviewed the turbulent model for the numerical simulations of high temperature flow fields. The physically based building fire model and the urban fire spread model are established for the prediction of the urban fire. Using these methods, some sample calculations have been carried out and examined the estimation of the hazard to evacuation due to wind-blown fire flows.