This paper discusses engineering aspects of the rear-flank downdraft that was recorded near Lubbock, Texas on 4 June 2002, and produced a gust wind speed nearly equal to the design value (50-year return period) for the region. The general characteristics of the storm, and the decomposition of the time histories into deterministic 'running mean' and random turbulence components are discussed. The fluctuating wind speeds generated by the event can be represented as a dominant low-frequency 'running-mean', with superimposed random turbulence of higher frequencies. Spectral and correlation characteristics of the residual turbulence are found to be similar to those of high-frequency turbulence in boundary-layer winds. However, the low-frequency components in the running-mean wind speeds are spatially homogeneous, in contrast to the low-frequency turbulence found in synoptic boundary-layer winds. With respect to transmission line design, this results in significantly higher 'span reduction factors'.

Item Type:	Refereed Article
Research Division:	Engineering
Research Group:	Fluid mechanics and thermal engineering
Research Field:	Turbulent flows
Objective Division:	Environmental Management
Objective Group:	Air quality, atmosphere and weather
Objective Field:	Atmospheric processes and dynamics
UTAS Author:	Letchford, CW (Professor Chris Letchford)
ID Code:	54295
Year Published:	2008
Web of Science® Times Cited:	85
Deposited By:	Centre for Renewable Power Energy Systems
Deposited On:	2009-02-16
Last Modified:	2009-09-03
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