查詢結果分析
來源資料
相關文獻
- Measurement on the Wind Characteristics for a Turbulent Boundary Layer Flow over Mild Slope Embankment
- 兩岸農產品出口在日、港競爭態勢之研究
- 非傳統式工法設計案例之探討
- Hepatodiaphragmatic Interposition of the Intestine (Chilaiditi's Syndrome)
- 防波堤可靠度評估模式之研究
- 離岸堤設計之日本經驗
- 波浪通過梯形潛堤之變形
- 白夜--杜斯妥也夫斯基[Fjodor Michajlovitsch Dostojevskij]的小說與維斯康堤[Luchino Visconti]的電影改編之間
- 淺談浮防波堤之發展
- 開孔型防波堤透過率之研究
頁籤選單縮合
| 題 名 | Measurement on the Wind Characteristics for a Turbulent Boundary Layer Flow over Mild Slope Embankment=紊流邊界層流越過緩坡度堤狀物之風場特性量測 |
|---|---|
| 作 者 | 蔡秉直; 蕭葆羲; | 書刊名 | 海洋工程學刊 |
| 卷 期 | 10:1 2010.06[民99.06] |
| 頁 次 | 頁49-63 |
| 分類號 | 443.31 |
| 關鍵詞 | 紊流邊界層流; 堤; 紊流強度; 雷諾應力; 增速; Turbulent boundary layer flow; Embankment; Turbulence intensity; Reynolds stress; Speed-up; |
| 語 文 | 英文(English) |
| 中文摘要 | 本文旨在量測分析研究紊流邊界層流越過二維緩坡度堤狀物(堤坡角度θ爲3˚, 6˚, 9˚, 12˚, 與 15˚)之平均風速與紊流特性變化。風速增速參數,K(下標 L)剖面量測結果顯示在堤頂處高度Z/Z(下標 ref)<0.4,K(下標 L)隨著堤坡角度增加而變大。此處Z爲高度,Z(下標 ref)爲紊流邊界層厚度。另在在堤頂處之紊流強度剖面與雷諾應力剖面在 Z/Z(下標 ref)>0.4,隨著堤坡角度增大,紊流強度與雷諾應力則未呈現顯著增加。若將風速加速參數,K(下標 L)結合堤坡坡度與與無因次高度等特性參數,轉換成另一無因次參數S(下標 p)。對於各堤坡角度之緩坡堤頂處,分析得出log[(Z/Z(下標 ref))/S(下標 p)]=-1.973log(θ)-0.204。堤頂處高度Z/Z(下標 ref)= 0.15之紊流風速能譜分析顯示:當紊流邊界層流越過堤狀物,堤坡角度由0˚增爲3˚時,低頻能譜密度增加;但隨著堤坡角度增加至15˚時,則低頻能譜密度減低。 |
| 英文摘要 | In the present study, we reported the measured results of the wind speed and turbulence characteristics for the turbulent boundary layer flow over a two-dimensional embankment with mild slope angle of 3˚, 6˚, 9˚, 12˚, and 15°. The measured profiles of wind speed-up parameter, K(subscript L) at the top of the embankment show that speed-up becomes significantly in the region of Z/Z(subscript ref) <0.4 as the embankment slope angle increases. Here Z is the measured height, and Z(subscript ref) is the turbulent boundary layer thickness. At the heights above Z/Z(subscript ref) >0.4, the differences for the longitudinal turbulence intensity and Reynolds stress become smaller, and they approach to almost the same for embankment with various slope angles. As the wind speed-up parameter, K(subscript L) is scaled by the dimensionless measured height and embankment slope. It is transformed to a dimensionless parameter, S(subscript p). Analysis of the relation between S p and embankment slope angle θ (in radian), the log-log linear function is found and shown as: log[(Z/Z(subscript ref)/S(subscript p)] = -1.973log(θ)-0.204. At the beginning location of embankment top surface with the height Z/Z(subscript ref)= 0.15, it is evident that the lower frequencies power density increase as the flow passed from 0˚ (no embankment existed) changing to embankment slope angle 3˚. But as the embankment slope angle is increasing up to 15˚, the lower frequencies power density decrease, inversely. |
本系統中英文摘要資訊取自各篇刊載內容。