教師資料查詢 | 類別: 會議論文 | 教師: 鄭啟明 CHENG CHII-MING (瀏覽個人網頁)

標題:紊流強度及長度尺度對二維方柱所受風力之影 響
學年79
學期1
發表日期1990/12/14
作品名稱紊流強度及長度尺度對二維方柱所受風力之影 響
作品名稱(其他語言)
著者鄭啟明; 盧博堅; 陳若華
作品所屬單位淡江大學土木工程學系
出版者
會議名稱中華民國力學學會第十四屆全國力學會議=The 14th National Conference on Theoretical and Applied Mechanics
會議地點桃園縣, 臺灣
摘要本文係以風洞模型試驗,設法分離紊流 強度與長度尺度,藉以探討各參數對於方柱模 型所受風力之影響。實驗參數的範圍為紊流強 度:T.I.=3%-18%,無因次長度尺度比 L/sub u//D=0.9-4.4。本文實驗在不同流 場條件與模型尺寸組合條件下量測方柱體所到 的平均阻力係數C/sub d/,擾動性阻力係數 C/sub d/',擾動性昇力係數C/sub 1/',順風向 風力頻譜,氣動力阻抗函數(Aerodynamic admittance function)及橫風向風力頻譜。由 實驗結果得知,平均阻力係數隨紊流強度增加 而遞減,擾動性阻力係數隨紊流強度增強而加 大。擾動性昇力係數隨長度尺度之增加而遞減 。並以紊流強度與長度尺度為基本變數,根據 實驗結果建立氣動力阻抗函數及橫風向風力頻 譜之經驗公式,其預測能力較平常用之經驗式 為佳。;This research project studied the turbulence effects on the aforementioned wind load characteristics on a 2D square cylinder through wind tunnel model tests. The range of controlled parameters were: turbulence intensity T.I.=3%-18%, length scale ratio L/sub x//D=0.9-4.4. Total of 27 flow conditions were studied in order to identify the individual effect of each turbulence characteristics on wind force coefficients and force spectra. Experimental results indicated that the mean drag coefficient. Cd, decreased with the increase of turbulence intensity. The fluctuating drag coefficient, Cd', increased with enhancement of turbulence intensity while insensitive to the variation of length scale ratio. The r.m.s lift coefficient, C/sub 1/', stayed invariant to the change of turbulence intensity but exhibited a significant trend of decrease with the increase of length scale ratio. Besides force coefficients, aerodynamic admittance functions and crosswind force spectra were obtaained . In this paper, both turbulence intensity and length scale were used as the basic parameter to derive the empirical model of alongwind admittance function and the crosswind force spectra. The present empirical models exhibited ability to predict wind force spectra to a satisfactory accuracy at various flow conditions.
關鍵字風洞;紊流強度;長度尺度;風力;阻力係數;升力係數;橫風向風力頻譜;Wind Tunnel;Turbulence Intensity;Length Scale;Wind Force;Drag Coefficient;Lift Coefficient;Crosswind Force Spectra
語言中文
收錄於
會議性質
校內研討會地點
研討會時間19901214~19901215
通訊作者
國別中華民國
公開徵稿Y
出版型式紙本
出處中華民國力學學會第十四屆全國力學會議論文集(二)=Proceedings of the 14th National Conference on Theoretical and Applied M=echanics (II)
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