Journal of Applied Fluid Mechanics (Jan 2019)
Non-Gaussian Wind Pressure Characteristics of HAWT Tower System with and Without Rotor
Abstract
Generally, the Gaussian assumption has been considered in analyzing the data pertaining to the wind effects on the structures or bluff bodies due to the abundance of the statistical information. In this study, Horizontal Axis Wind Turbine (HAWT) tower system with dimension of 1:330 scale is studied in order to understand their peak pressure behavior for wind resistant design. Generally, tower systems are constructed of various geometrical structures such as lattice towers, tubular steel towers, concrete towers, but in this present study tubular cylindrical tower is only considered. Simultaneous pressure measurements on the surface of the tower were performed in the low-speed boundary layer wind tunnel with test section dimension of 18 m × 2.5 m × 2.15 m having Reynolds number ranging from 102 to 104. The peak pressures acting on the tower systems are calculated for a number of ten-minute samples on various locations of the wind turbine. Peak value calculations based on Gaussian and Non – Gaussian processes are discussed mathematically and applied to the data collected from the wind tunnel tests. A mathematical model of Davenport and Kareem – Zhou is used in calculating the peak factor for Gaussian and non – Gaussian processes, respectively. The results indicate that higher moments dominate as most of the distribution is skewed and with kurtosis value. Henceforth, a study on extreme value analysis is deemed necessary in designing wind resistant structures or bluff bodies. Considering Gaussian nature alone may under-represent the peak value of the HAWT tower.
