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外文期刊>American journal of applied sciences
>EVALUATION OF THE ADEQUACY OF THE WIND SPEED EXTRAPOLATION LAWS FOR TWO DIFFERENT ROUGHNESS METEOROLOGICAL SITES | Science Publications
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EVALUATION OF THE ADEQUACY OF THE WIND SPEED EXTRAPOLATION LAWS FOR TWO DIFFERENT ROUGHNESS METEOROLOGICAL SITES | Science Publications
> Increasing knowledge on wind shear models to strengthen their reliability appears as a crucial issue, markedly for energy investors to accurately predict the average wind speed at different turbine hub heights and thus the expected wind energy output. This is particularly helpful during the feasibility study to abate the costs of a wind power project. The extrapolation laws were found to provide the finest representation of the wind speed according to heights, thus avoiding installation of tall towers, or even more expensive devices such as LIDAR or SODAR. The proposed models are based on theories that determine the vertical wind profile from implicit relationships. However, these empirical extrapolation formulas have been developed for specific meteorological conditions and appropriate sites for wind turbines; reason that several studies have been made by various authors to determine the best suited formula to their own conditions. This study is aimed at proceeding the research issue addressed within a previous study, where some extrapolation models were tested and compared by extrapolating the energy resources at different heights. However, comparable results are returned by the power law and the log law which indeed proved to be preferable. In this context, this study deals the assessment of several wind speed extrapolation laws (six laws), by comparing the analytical results obtained with real data for two different meteorological Sites, different roughness, different altitudes and different measurement periods. The first site studied is an extremely rough site with daily measurements of March 2007, wind speed measurements are available at four different heights of Gantour/Gao site, obtained by the water, energy and environment company Senegal. The second site studied is a feeble rough site with monthly measurements for 2005, wind speed measurements are available at three different heights of Kuujjuarapik Site obtained by Hydro-Quebec Energy Helimax Canada. The study aims to determine the effectiveness and concordance between the extrapolation laws and the real measured data. The results show that the adjusted law is efficiently adequate for an extremely rough site and the modified laws with two other laws are efficiently adequate for a feeble rough site. The experimental results and numerical calculations exploited for the evaluation of the Weibull parameters fall the shape factors k greater than 9. The increase in altitude often causes an increase in the Weibull parameters values, however, our results show that the shape factor k can take lower values to those established in the reference altitude.
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机译： >增加对风切变模型的了解以增强其可靠性似乎是一个至关重要的问题，这对于能源投资者而言，显然是要准确地预测不同涡轮机轮毂高度处的平均风速，从而准确地预测风能输出。这在进行可行性研究以降低风电项目成本的过程中特别有用。发现外推法则可以根据高度提供风速的最佳表示，从而避免安装高塔或什至更昂贵的设备（如LIDAR或SODAR）。所提出的模型基于从隐式关系确定垂直风廓线的理论。但是，这些经验外推公式是针对特定的气象条件和风力涡轮机的合适地点而开发的。各种作者进行了几项研究，以确定最适合自己情况的配方的原因。这项研究旨在进行先前研究中解决的研究问题，在该研究中，通过推断不同高度的能源来测试和比较了一些推断模型。但是，幂定律和对数定律返回了可比的结果，事实证明它们是更可取的。在这种情况下，本研究通过将获得的分析结果与两个不同气象站点，不同粗糙度，不同海拔和不同测量周期的真实数据进行比较，对几种风速外推定律（六个定律）进行了评估。研究的第一个站点是一个非常粗糙的站点，每天进行2007年3月的测量，可以从塞内加尔的水，能源和环境公司获得的Gantour / Gao站点的四个不同高度进行风速测量。研究的第二个站点是一个微弱的粗糙站点，2005年每月测量一次，在加拿大Hydro-Quebec Energy Helimax公司获得的Kuujjuarapik站点的三个不同高度上可以进行风速测量。该研究旨在确定外推法则与实际测量数据之间的有效性和一致性。结果表明，调整后的定律对于极端粗糙的场地有效，而修改后的定律与另外两个定律对脆弱的粗糙场地有效。用于评估Weibull参数的实验结果和数值计算会使形状因子k大于9。高度的增加通常会导致Weibull参数值增加，但是，我们的结果表明形状因子k可以降低值是在参考高度中确定的值。
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