Analysis and simulation tools for wind engineering

This paper examines state-of-the-art analysis and simulation tools for applications to wind engineering, introduces improvements recently developed by the authors, and directions for future work. While the scope of application extends to a variety of environmental loads (e.g. ocean waves and earthquake motions), particular reference is made to the analysis and simulation of non-Gaussian features as they appear in wind pressure fluctuations under separated flow regions and non-stationary characteristics of wind velocity fluctuations during a gust front, a thunderstorm or a hurricane. A particular measured non-Gaussian pressure trace is used as a focal point to connect the various related topics herein. Various methods of non-linear system modeling are first considered. Techniques are then presented for modeling the probability density function of non-Gaussian processes. These include maximizing the entropy functional subject to constraints derived from moment information, Hermite transformation models, and the use of the Kac-Siegert approach based on Volterra kernels. The implications of non-Gaussian local wind loads on the prediction of fatigue damage are examined, as well as new developments concerning gust factor representation of non-Gaussian wind loads. The simulation of non-Gaussian processes is addressed in terms of correlation-distortion methods and application of higher-order spectral analysis. Also included is a discussion of preferred phasing, and concepts for conditional simulation in a non-Gaussian context. The wavelet transform is used to decompose random processes into localized orthogonal basis functions, providing a convenient format for the modeling, analysis, and simulation of non-stationary processes. The work in these areas continues to improve our understanding and modeling of complex phenomena in wind related problems. The presentation here is for introductory purposes and many topics require additional research. It is hoped that introduction of these powerful tools will aid in improving the general understanding of wind effects on structures and will lead to subsequent application in design practice.