抄録
Wind tunnel experiments concerned with the air flow around a model building are conducted. The hot-wire anemometer is made for trial which has little directivity of standard deviation of turbulence in plane at right angles to hot-wire and its characteristics are tested. The distributions of air flow speed and turbulent structures around a model are measured using the hand-made hot-wire in relation to the roughness parameter Z_0 of approaching flow. The following conclusions can be drawn. (1) On the distributions of air flow speed around a model building ; increased ratio of standard deviation of turbulence [numerical formula] equals to about 2.2〜3.0 and is larger than that of mean speed U_M/U_S. The area of increased [numerical formula] decreases as roughness parameter Z_0 becomes larger. (2) On the turbulent structure of air flow around a model building ; peak frequency of power spectra moves to lower frequency range as Z_0 becomes larger. Distribution of probability density can be fitted with normal distribution considerably well in the area of increased mean speed.
