Characterizing Wind Gusts in Complex Terrain

TitleCharacterizing Wind Gusts in Complex Terrain
Publication TypeJournal Article
Year of Publication2019
JournalAtmospheric Chemistry and Physics
Volume19
Number6
Pages3797-3819
Date Published03/2019
Abstract

Wind gusts are a key driver of aerodynamic loading, especially for tall structures such a bridges and wind turbines. However, gust characteristics in complex terrain are not well understood and common approximations used to describe wind gust behavior may not be appropriate at heights relevant to wind turbines and other structures. Data collected in the Perdigão experiment are analyzed herein to provide a foundation for improved wind gust characterization and process-level understanding of flow intermittency in complex terrain. High-resolution observations from sonic anemometers and vertically pointing Doppler lidars are used to conduct a detailed study of gust characteristics with a specific focus on the parent distributions of nine gust parameters (that describe velocity, time and length scales), their joint distributions, height variation and coherence in the vertical and horizontal planes. Best-fit distributional forms for varying gust properties show good agreement with those from previous experiments in moderately complex terrain but generate non-conservative estimates of the gust properties that are of key importance to structural loading. Probability distributions of gust magnitude derived from vertical pointing Doppler lidars exhibit good agreement with estimates from sonic anemometers despite differences arising from volumetric averaging and the terrain complexity. Wind speed coherence functions during gusty periods (which are important to structural wind loading) are similar to less complex sites for small vertical displacements (10 to 40 m) but do not exhibit an exponential form for larger horizontal displacements (800 to 1500 m).

URLhttp://dx.doi.org/10.5194/acp-19-3797-2019
DOI10.5194/acp-19-3797-2019
Journal: Atmospheric Chemistry and Physics
Number: 6
Volume: 19

Wind gusts are a key driver of aerodynamic loading, especially for tall structures such a bridges and wind turbines. However, gust characteristics in complex terrain are not well understood and common approximations used to describe wind gust behavior may not be appropriate at heights relevant to wind turbines and other structures. Data collected in the Perdigão experiment are analyzed herein to provide a foundation for improved wind gust characterization and process-level understanding of flow intermittency in complex terrain. High-resolution observations from sonic anemometers and vertically pointing Doppler lidars are used to conduct a detailed study of gust characteristics with a specific focus on the parent distributions of nine gust parameters (that describe velocity, time and length scales), their joint distributions, height variation and coherence in the vertical and horizontal planes. Best-fit distributional forms for varying gust properties show good agreement with those from previous experiments in moderately complex terrain but generate non-conservative estimates of the gust properties that are of key importance to structural loading. Probability distributions of gust magnitude derived from vertical pointing Doppler lidars exhibit good agreement with estimates from sonic anemometers despite differences arising from volumetric averaging and the terrain complexity. Wind speed coherence functions during gusty periods (which are important to structural wind loading) are similar to less complex sites for small vertical displacements (10 to 40 m) but do not exhibit an exponential form for larger horizontal displacements (800 to 1500 m).

DOI: 10.5194/acp-19-3797-2019
Year of Publication: 2019
Citation:
Letson, F, R Barthelmie, W Hu, and S Pryor.  2019.  "Characterizing Wind Gusts in Complex Terrain."  Atmospheric Chemistry and Physics 19(6): 3797-3819, doi:10.5194/acp-19-3797-2019.