ABSTRACT
Non-stationary features existing in tropical storms have been frequently captured in recent field measurements, the applicability of the stationary theory to the analysis of wind characteristics needs to be discussed. In this study, a tropical storm which is named as Nakri measured at Taizhou Bridge site in China in 2014 is analyzed to give a comparison of the stationary and non-stationary wind characteristics. The stationarity of the wind records in the view of mean value and variance is first evaluated with the commonly used run test method. Then the wind data are respectively analyzed with the traditional stationary wind model and the wavelet-based non-stationary wind model. During the analytical procedure, the multi-level wavelet transform provides an efficient approach to extract the time-varying trend from the original wind records, which takes the filtering function with the aid of Mallat algorithm. The obtained stationary and non-stationary wind characteristics such as the mean wind velocity, turbulence intensity, turbulence integral scale and power spectral density (PSD) are emphatically compared accordingly. Meanwhile, the stationary and non-stationary PSDs of along-wind turbulence are fitted to present the turbulence energy distribution in frequency domain, among which a modulating function is included in the non-stationary PSD to revise the non-monotonicity of the measured non-stationary PSD. The results of this study recommend a transition from stationarity to non-stationarity in the analysis of severe wind characteristics (e.g. tropical storm), and further in the accurate prediction of wind-induced vibrations for engineering structures. Comparison of mean wind velocities from stationary and non-stationary models. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315207681/cd556cd4-4dcf-4efe-8e29-56fc67b8bfbd/content/fig308_1.tif"/>
