Evaluation Of The Non-stationary Wind And Its Effect On Structural Wind Loads

The natural wind normally has the characteristic of nonstationarity. Structural wind load under non-stationary wind is different from that under stationary wind. With the help of the method which is used to identify the Non-stationary of data flow in mathematic area, the identification process of the Non-stationary wind speed has been introduced in this thesis based on the results of full scale measurments. Meanwhile, this thesis presents a quantitative index in terms of non-stationary according to the existing non-stationary signal processing methods. Also in this project, the actual non-stationary wind has been simulated with CFD, the changes of structural wind load under non-stationary wind has been analysed, different effects of non-stationary and stationary wind speed on structural wind load distribution has been compared. The main content of this thesis includes:(1) To discuss different processing means of non-stationary signal. To bring the mathematical assessment technique of data flow into the field of wind engineering and propose a method with quantitative index to evaluate the nonstationarity of wind speed.By using this method, the non-stationarity wind speed derived from full sacle measurements in different regions has been test。(2) By integrating the EMD and Non-stationary index, the effects of long and short period components of wind speed on the non-stationarity has been studied.(3) On the inputting condition of Ideal linear increasing wind speed and wind data from full scale measurements, the project use LES model, study the differences between the wind load on structural surface under non-stationary wind speed and that under stationary wind speed. The project studies the difference of wind loads on structural surface under wind speed with different stationarity and evaluates the effect of non-stationary wind on structural wind load.