Studies on the relationships between the local topography and the damages of buildings hit by Typhoon - Model test of topography used boundary layer wind tunnel -

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We have analyzed the topographical effects of wind forces for many years. Using statistic meghod,we analyzed the relationship between the damage distribution of buildings resulting from typhoon and it's meteorological observation data such as wind velocity and direction. However these methods are limited and obtaining available design data concerning the topographic effects is difficult.To obtain the basic data,we carried out wind tunnel tests,unmerical simulations on the finite element method and site meteorological observations at Myogane Promontory,Futtsu City,Chiba Pregecture. In this study, we obtained the following conclusions.1.Wind tunnel tests on the simplified topographic model. (1) We clarified the wind flow pattern over the various angles of the inclination of hills (slope angles ; 10 ,15 ,30 ,45 ,60 ) and proposed a distribution map of wind speed increment coefficient S(X/Le,H/Le)(where the brackets denote functional dependence on the position frow the crest X and the heigh above ground H in terms of the upwinf slope length Le). (2) We also analyzed the relationship between the wind speed ratio (V/Vo;Vo is the incident mean wind speed) and the distance from the crest of hills(Lx)or the height ratio (H/Ho:Ho is the height of hill). (3) Using the finite element method, we showed the growth and transfer of vortex and belamination condition over the various angles of the inclination of hills.2. Comparing the site meteorological observation data with the model wind tunnel test data at Myogane Promontory. (1) We clarified the distribution condition of wind direction and wind velocity when winds blew in northerly and southeasterly directions. (2) We proposed cartain methodology regarding topography model experiments.