【作者】 余子牛；

【导师】 苑明顺；

【作者基本信息】 清华大学 ， 水力学及河流动力学， 1996， 硕士

【摘要】 明渠水流运动在实际工程中广泛存在，其数值模拟研究有现实意义。桥墩壅水是在防洪标准低、防洪费用高的平原河道上修建桥梁时必须重点考虑的问题之一，其研究具有重要价值。本论文采用非规则贴体网格有限体积法和显式MacCormack预测-校正法求解平面二维水深积分方程，对明渠水流运动的数值模拟方法进行了研究，并且应用该数值模型计算了14种不同的桥墩体型、来流、收缩比的组合工况下的桥墩壅水问题。采用模型试验资料验证了壅水高度计算结果。非规则贴体网格有限体积法可以真实模拟复杂形状边界，提高边界附近的计算精度，能够较其他方法更理想地处理明渠水流中常常遇到的复杂边界问题，在这点上比只能构造少的单元数的有限单元法和一般采用矩形网格的有限差分法优越。壅水高度的计算结果与模型试验资料吻合较好，证明了数值模型是可靠的。此外，本论文还初步研究了网格局部加密方法并应用于桥墩局部绕流流场的研究。网格局部加密方法的应用明显的改善了加密区域内的结果，对加密区域外的流场也有一定的改进，具有一定的应用前景。更多还原

【Abstract】 Open channel flow exists widely and its numerical simulation is of reality. The damming caused by a bridge pier is one of the aspects considered intentionly while building a bridge on a river which flood control standard is low and flood control cost is high so the study of damming is of important value.In this thesis a numerical model to solve the planear 2-D Depth-Integrated Flow(DIF) has been established with irregular body-fitted mesh Finite Volume Method and explicit MacCormack predictor-corrector method and applied to the study of damming caused by a bridge pier under 14 working conditions varied with the combination of different pier shape . flow rate and contraction ratio. The experimental results in a physical model are adopted to verify the simulated damming heights.Irregular body-fitted mesh Finite Volume Method can really simulate complicated boundaries and improve the predicting precision so it is more ideal to process the complicated boundaries met often in open channels. In this point of view this approach is better than Finete Element Method in which only few elements can be used and Finite Diffence Method in which the rectangular grid is always used.That the predicted values of damming height agree well with the exprimental results proves the validity of the numerical model.In the addition, the locally refining mesh method has been studied preliminarily and applied to the study of the local flow around a bridge pier. It is found that the use of the locally refining mesh method can improve the results in the refined area greatly, and can improve the results outside the refined area to a certain extent too. This method has the potential application in studying many problems with the great characteristic size ratio .更多还原