市街地における建物の密度変化に伴う風速の鉛直分布形状の変化について

Abstract

Configurations of buildings and houses in real urban cities were obtained from maps and aerial photographs.The relation of the number, the scale and the volume of houses and buildings against the number of stories were evaluate from these data.Using these results, three model cities which have different characteristics of roughness configuration in the composition of number of stories were generated virtually.The first model city mainly consists of low rise houses up to 3 storied.The second one consists of low rise houses and middle rise buildings up to S storied.The third consists of middle and high rise buildings up to 10 storied.Numerical simulations of wind flows under nutral, strong wind condition over these model cities were carried out.Variations of wind characteristics of turbulent boundary layer with the building density were estimated.The calculated values showed that the mean wind speed decreases, the intensity of turbulence and the virtical gradient of mean wind speed increase when the building density increaes.The variation of these results becomes the largest in case of the second model city which consists of low rise houses and middle rise buildings.Finally predicted values of power law exponent a of the wind speed profiles for the wind resistent desigu were presented against the variation of the building density of these three model cities.