頁籤選單縮合
題 名 | 橫向流場中浮昇射流之實驗研究=An Experimental Study of Buoyant Jets in Currents |
---|---|
作 者 | 朱佳仁; 吳瑞賢; 梁天堯; 詹國華; | 書刊名 | 中國土木水利工程學刊 |
卷 期 | 10:3 1998.09[民87.09] |
頁 次 | 頁485-493 |
分類號 | 440.137 |
關鍵詞 | 浮昇射流; 紊流橫向流; 軌跡; 稀釋率; Buoyant jet; Turbulent current; Trajectory; Dilution; |
語 文 | 中文(Chinese) |
中文摘要 | 本研究以因次分析及實驗方式來探討層流橫向流和紊流橫向流對單管水平及重 直浮昇射流之影響,實驗在一靜止的水槽中以台車拖曳排放鹽水的射流管來模擬橫向流場中 的浮昇射流,紊流橫向流則於射流管前放置一格網隨台車移動來產生。實驗中使用熱膜流速 儀量測格網紊流之紊流強度,以影像處理來擷取浮昇射流的軌跡,以螢光染料和濃度採樣器 來量測射流的濃度分佈和稀釋率。實驗結果顯示射流軌跡及稀釋率皆可用浮昇射流之特性長 度尺度加以量化,但射流之稀釋率及濃度寬度皆會隨著橫向流中周遭紊流的增強而增大,且 紊流橫向流中的射流軌跡會低於層流橫向流中的軌跡。前人對射流的研究中往往忽略了橫向 流場中的紊流效應,亦即一般依據層流橫向流所建構之預測模式可能會低估實際紊流海域中 所發生的稀釋率,所以探討浮昇射流排放於自然界流場時應考慮周遭紊流對其所產生的影響 。 |
英文摘要 | Most previous laboratory experiments on jets mixing with ambient curents were carried out by towing turbulent jets through stagnant receiving water. In this way, the ambient current is laminar and the influence of ambient turbulence on the initial phases of the jet mixing was ignored. This study investigates the influence of a laminar and turbulent current on buoyant jets by the towing of a vertical grid in front of buoyant jets in a laboratory flume. Turbulence intensity behind the grid was measured by a hot-film anemometer. The trajectory and concentration distributions of buoyant jets were measured by an image processing method and a concentration sampling system. The experimental conditions include horizontal and vertical single port discharges. The experimental results reveal that the minimum dilution increases with increasing turbulence intensity. Furthermore, due to the enhancement of jet mixing in a turbulent current, the jet trajectory was found to be lower than in a laminar current. This indicates that the influence of ambient turbulence on the initial phase of jet mixing cannot be ignored. |
本系統中英文摘要資訊取自各篇刊載內容。