动量修正系数对恒定明渠流计算的影响

发布时间：2018-05-07 14:15

本文选题：交替方向隐式格式(ADI) + 急流　；参考：《水动力学研究与进展(A辑)》2017年05期

【摘要】：在采用浅水方程的洪水模拟中,经典的交替方向隐式格式(ADI)被认为不能用来计算跨临界流。这种格式会在自由水面和流速急剧变化的地方产生非物理振荡。然而,实际中这种格式仍然被广泛应用于商业计算软件。为了能够用ADI格式在模拟跨临界流时能够得到稳定的数值结果,修改动量修正系数(Boussinesq系数)这种数值处理方法能够部分地减轻ADI模型在模拟跨临界流时遇到的困难。该文通过对一维恒定流条件下的高速明渠流动问题的数值模拟,以及二维英国Boscastle地区洪水波的数值模拟,系统地评估了这种数值处理方法对模型计算的影响,并对比了ADI和具有激波捕捉能力的TVD-Mac Cormack模型的计算结果。结果表明,随着动量修正系数的减小,可以有效抑制ADI格式产生的数值振荡,但同时会降低水深的预测值。这些结果有助于评估数值格式在模拟跨临界流动时的准确性。
[Abstract]:In flood simulation using shallow water equations, the classical alternating direction implicit scheme (ADI) is considered to be unable to be used to calculate transcritical flows. This format produces non-physical oscillations in free water and where the velocity changes dramatically. However, in practice, this format is still widely used in commercial computing software. In order to obtain stable numerical results by using ADI scheme in simulating transcritical flow, the modified momentum correction coefficient and Boussinesq coefficient are modified. This numerical method can partially alleviate the difficulties encountered by the ADI model in simulating transcritical flow. In this paper, the influence of this numerical treatment method on the model calculation is systematically evaluated by the numerical simulation of high speed open channel flow under the condition of one dimensional constant flow and the numerical simulation of two dimensional flood waves in the Boscastle region of England. The results of ADI and TVD-Mac Cormack model with shock capture ability are compared. The results show that the numerical oscillation generated by the ADI scheme can be effectively suppressed with the decrease of the momentum correction coefficient, but the predicted value of the water depth will be reduced at the same time. These results help to evaluate the accuracy of numerical schemes in simulating cross-critical flows.
【作者单位】：上海交通大学;剑桥大学;
【基金】：国家自然科学基金项目(11632012) 英国牛顿委员会基金(UK-275929921)~~
【分类号】：TV133

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