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Title: Vertical extrapolations of wind speed

Abstract

The extrapolation of wind speeds and wind speed distributions from a lower to an upper level is examined, with particular emphasis on the power law approach. While the power laws are useful for representing the behavior of winds under a variety of conditions, they are shown to be inherently incorrect and misleading for extrapolations. The law's apparent simplicity nevertheless makes it attractive for certain purposes, and its performance at a number of windy sites is tested. The principal feature seems to be the large degree of scatter found from site to site, and even at a single site from one time to the next. Part of this is attributable to the effects of stability, as is seen by dividing the data into daytime and nighttime periods, but the scatter is by no means eliminated by this division. The behavior of the power law exponents is poorer still in complex terrain. While some general tendencies of these exponents can be found, their use cannot be recommended for anything more than a preliminary or rough estimate of wind speeds. Extrapolation formulas for Weibull distributions are also tested with the same data base. They are found to work reasonably well in the mean,more » but the uncertainties present make their use in any particular case somewhat risky. The use of kites to obtain estimates either of wind speed distributions or power law exponent distributions is simulated. As expected, there is a considerable degree of scatter associated with the results, but the use of kites seems to offer some small possibility of improvement compared to results obtained from the simple extrapolation formulas for Weibull distributions.« less

Authors:
; ;
Publication Date:
Research Org.:
Pacific Northwest Lab., Richland, WA (USA)
OSTI Identifier:
7097248
Report Number(s):
PNL-4361
ON: DE83000944
DOE Contract Number:
AC06-76RL01830
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
17 WIND ENERGY; WIND; CALCULATION METHODS; DISTRIBUTION FUNCTIONS; DATA COVARIANCES; EXPERIMENTAL DATA; EXTRAPOLATION; MEASURING METHODS; STABILITY; THEORETICAL DATA; VARIATIONS; VELOCITY; DATA; FUNCTIONS; INFORMATION; NUMERICAL DATA; NUMERICAL SOLUTION; 170100* - Wind Energy- Resources & Availability (Climatology)

Citation Formats

Doran, J.C., Buck, J.W., and Heflick, S.K.. Vertical extrapolations of wind speed. United States: N. p., 1982. Web. doi:10.2172/7097248.
Doran, J.C., Buck, J.W., & Heflick, S.K.. Vertical extrapolations of wind speed. United States. doi:10.2172/7097248.
Doran, J.C., Buck, J.W., and Heflick, S.K.. Wed . "Vertical extrapolations of wind speed". United States. doi:10.2172/7097248. https://www.osti.gov/servlets/purl/7097248.
@article{osti_7097248,
title = {Vertical extrapolations of wind speed},
author = {Doran, J.C. and Buck, J.W. and Heflick, S.K.},
abstractNote = {The extrapolation of wind speeds and wind speed distributions from a lower to an upper level is examined, with particular emphasis on the power law approach. While the power laws are useful for representing the behavior of winds under a variety of conditions, they are shown to be inherently incorrect and misleading for extrapolations. The law's apparent simplicity nevertheless makes it attractive for certain purposes, and its performance at a number of windy sites is tested. The principal feature seems to be the large degree of scatter found from site to site, and even at a single site from one time to the next. Part of this is attributable to the effects of stability, as is seen by dividing the data into daytime and nighttime periods, but the scatter is by no means eliminated by this division. The behavior of the power law exponents is poorer still in complex terrain. While some general tendencies of these exponents can be found, their use cannot be recommended for anything more than a preliminary or rough estimate of wind speeds. Extrapolation formulas for Weibull distributions are also tested with the same data base. They are found to work reasonably well in the mean, but the uncertainties present make their use in any particular case somewhat risky. The use of kites to obtain estimates either of wind speed distributions or power law exponent distributions is simulated. As expected, there is a considerable degree of scatter associated with the results, but the use of kites seems to offer some small possibility of improvement compared to results obtained from the simple extrapolation formulas for Weibull distributions.},
doi = {10.2172/7097248},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Sep 01 00:00:00 EDT 1982},
month = {Wed Sep 01 00:00:00 EDT 1982}
}

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