Three dimensional non-stationary analysis on field measured wind data with coupling wind speed and wind direction

In order to investigate the three dimensional non-stationary characteristics of field measured wind data with the joint effect of wind speed and direction, a three-dimensional non-stationary wind speed model was proposed. The corresponding formula was established by utilizing the empirical modal decomposition (EMD) method to obtain the time history of the three dimensional fluctuating wind speed. Some continuous variables related to wind characteristics, such as the time-varying standard deviation and time-varying turbulence intensity, were furthermore proposed. In order to verify the accuracy of the proposed method, the field measured three dimensional wind data during the passage of typhoon over a high-rise building was adopted to investigate its non-stationary characteristics comprehensively by comparing with the traditional stationary wind data analysis model. The analyzed results show that the proposed method is not only accurate but also has good performance in the following aspects: no specific time interval is needed for the statistical analysis on the measured wind data; the local fluctuating characteristic and non-stationary characteristics could be described more clearly. Finally the analysis results on the stationary performance of the measured wind data are verified by the stationary index. The results show that the stationary index of the measured wind speed increases with the frequency and related to its varying rate. Furthermore the stationary performance of fluctuating wind speed obtained by the proposed non-stationary wind speed model is found to be more reasonable than that obtained by the traditional stationary wind model. © 2016, Science Press. All right reserved.