陡坡渠道之特性為其水流之含氣現象 ,但含氣率之量測頗為不易。本研究應用定溫 式熱膜流速儀對於空氣與水熱傳導特性不同及 其高頻率反應之特性而量測陡坡渠道物理模型 之水流及其含氣率。含氣率之決定是以輸出電 壓配合統計理論之應用,而求得一檢測氣泡信 號之臨界電壓值,藉臨界電壓值過濾氣泡之反 應電壓並假設亂流水體擾動之反應電壓值為常 態分布而求得流速與含氣率。而常態分布之可信度則以開方適合度試驗法(Chi-square)檢定 ,並根據量測之流速與含氣率計算斷面流量而 與試驗流量比較知其正確性。本研究更以試驗 數據配合因次分析,探討含氣率與各流況水理 因子,如坡度與流量,之關係。 The characteristic of open channel chute flow is its self-aerated phenomenon. Use of the hot film anemometer together with the statistical theorem are proved to be a successful method for the measurement of air concentration in the open channel chute flow. The determination of the threshold value or the critical value of the ouput voltage for determining the air concentration is presented in this study. Based on dimensional analysis, the cross sectional mean air concentration is related to Reynold number, Froude number, and bed slope.
關聯:
第五屆水利工程研討會論文集(一)=Proceedings of 5th Conference on Hydraulic Engineering，頁478-489
