Estimation of peak factor and gust factor of nonstationary wind speed

Abstract

This paper proposes a new method for estimating the peak factor and gust factor of nonstationary wind. In this method, the probability density function (PDF) of the largest value of a nonstationary wind speed is fitted using the PDF of the largest value of an equivalent stationary wind speed; subsequently the mean wind speed and standard deviation of the equivalent stationary wind speed, which are respectively defined as equivalent mean wind speed and equivalent standard deviation, are used to normalize the largest value of the nonstationary wind speed to calculate its gust factor and peak factor. The proposed method can be utilized in the field measurement of nonstationary wind speed to obtain peak factor and gust factor which might be applicable for predicting the largest value of a new nonstationary wind speed only using its time-varying mean wind speed and time-varying standard deviation. The applicability of the proposed method is verified using numerical simulation and wind speed data of three typhoons, which were measured atop the Shanghai World Financial Center (SWFC) at a height of 497 m. The three typhoons’ peak factor and gust factor estimated by the proposed method are also analyzed in this study.