本研究提供了風力發電機與透孔盤模型在風洞大氣邊界層中的尾流速度場量測結果，實驗於內政部建研所之低速循環式環境風洞中的第一測試段進行，截面積為4m×2.6m，長21m。使用兩組模型來模擬風機，分別為轉子式及透孔盤模型，並將實驗分為兩組不同變因之比較，來分別比較模型與邊界層厚度不同對尾流造成之影響。實驗以移動機構裝置Dantec公司之Stream Line 量測系統搭配二維熱線探針55P61，來量測模型尾流的速度分佈，並搭配轉子式風速計Dp-103量測來流風速。

實驗分為兩組，第一組實驗為不同大氣邊界層厚度對風力發電機尾流之影響，來流風速約為5m/s，邊界層厚度分別為1.85D及5.55D，都使用轉子式風機模型，且固定翼尖端速度比λ為0.113，量測至模型x=7D之剖面。第二組實驗為不同模型之尾流特性差異，來流風速約為5m/s，邊界層厚度為5.5D，使用透孔盤與轉子式模型進行比較，轉子式風機模型之λ為0.13，量測至模型x=7D之剖面。
依序分析各剖面之流場均勻度、風速分佈、紊流強度分佈、紊流積分尺度與雷諾應力，並使用HHT分析來探討尾流區內的紊流擾動能量分佈。比對分析結果之流場均勻度、平均風速和紊流強度等資料後，轉子式模型尾流於邊界層較薄的狀況下發展距離較短，呈現模型本身尾流效應會與大氣邊界層交互作用並影響尾流發展距離與特徵，於風力發電機設置時須考慮大氣邊界層與風機之比例與尾流發展距離之關係。而透孔盤因推力系數較大，產生之尾流效應較強，並有較長之尾流發展距離，同時發現轉子式模型呈現的尾流是非對稱的，也造成透孔盤模型於模擬風力發電機尾流之減風作用。

於HHT能量頻譜分析中得到兩組實驗中的紊流擾動能量組成，與來流之比較發現通過模型的的高頻擾動能量組成比例增加，然後隨距離的增加而逐步降低。於本實驗中的各組數據皆能發現此現象，探討後發現若邊界層較高，現象較不明顯，於不同模型之比較中發現轉子式模型之尾流擾動於高頻之比例較高，使用透孔盤於模擬風力發電機尾流於時須將擾動之能量頻譜，也就是紊流組成結構納入考量。

SUMMARY

This paper examines experimentally the wake characteristics of a model wind turbine and a porous disk in turbulent boundary layers, respectively. The experiments simulating the atmospheric boundary layer flow condition were conducted in an environmental wind tunnel. Under the experimental condition, two boundary layers of different thickness, about 5.5D and 1.85D, where D denotes the diameter of model blade. The velocity measurements were based on the hot-wire anemometer. Hilbert Huang Transform had been used to analysis the turbulent characteristics. The result shows that velocity deficit was decrease in the thicker boundary layer, and had less turbulent-increase effect in the thicker boundary layer. The relationship between velocity deficit and turbulence intensity increase were in direct proportion, but porous disk shows they were in reverse proportion. The turbulent integral time scale shows large turbulent eddies dominated the turbulence in the thicker boundary layer, and small turbulent eddies dominated the turbulence in the thinner boundary layer. The strouhal number from the main turbulent frequency was consistent with the results of turbulent integral time scale. The wake flow development in the thicker boundary layer appear to be dominated by the large scale eddies in the boundary layer, whereas in the thinner boundary layer, the wake flow development relies on the turbulent eddies generated by the model.

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