Studies on Spatial Structure of Wind Gust

Abstract

The peak gust speed is often used to evaluate the maximum wind tome acting on the structure in wind engineering. To evaluate this peak gust speed, the ratio of the peak gust speed over the mean wind speed (called gust factor) is defined. The peak gust is an averaged value of wind speed over a very short duration and small space and is the function of those averaging parameters as well as turbulent conditions. Experimental relation of the gust factor on the averaging time and space was studied by the results of a typhoon wind experiment made on Tarama Island in the Southwest Islands of Japan. The gust factor is independent from mean wind speed in winds higher than 14 m s?1. The dependence of the gust factor on the averaging time is well described by a formula proposed previously by one of the authors and can be explained as the mean normal extreme of wind fluctuations. The space averaging the gust factor is also described by a new experimental formula of exponential form.