以數值模擬探討高含砂效應對渠流流況之影響

Abstract

楊與謝(2003)發展一水深平均二維水理模式，鍾(2007)進一步考量非牛頓流體之流變關係，將模式擴充為高含砂水流模式。本研究以上述兩模式為基礎，藉此探討高含砂水流對明渠水流水深、流速與剪力之效應，並分析其影響程度，其結果可提供與模式使用者作為選用合適模式之參考。

A numerical experiment is carried out to study the hyperconcentrated flow behavior in open channel. Two kinds of 2D depth-averaged model are considered in this study of which the hyperconcentrated flow model (Chung 2007) includes the Newtonian and non-Newtonian fluid rheological relations in bottom shear stress, and the clear flow model (Yang and Hsieh 2003) only includes the effect of Newtonian fluid in bottom shear stress. The maximum relative discrepancy of the depth, velocity, and shear stress obtained from the comparison of these two models, are use as the criterion to judge the hyperconcentrated effect on open channel flow. The results can provide a guideline for model users to determine the proper approach to simulate the hyperconcentrated flow problem by either using the clear flow model or the hyperconcentrated flow model.