Based on the principle of water volume balance and kinematic-wave (KW) model, those models are disposed with dimensionless, which to improve simulation accuracy of water movement process with water volume balance model. The changes of surface shape factor were studied and it could be computed with empirical formula which was proposed in this paper. Research results showed that the surface shape factor was not a constant value, but a variable value with the change of irrigation time, water advance distance and other factors. The validity of the proposed method was verified by some research materials, the results showed that the precision of the model could be improved when the variation of surface shape factor was considered using volume balance model and the empirical formula proposed. The model was applied to estimate water surface shape factor for forder irrigation was reliable.%为了提高水量平衡模型模拟水流运动过程的精度.以水量平衡原理为基础,结合动力波(KW)模型,通过对其无量纲化,研究了畦灌过程中的地表储水形状系数变化规律并提出了估算其值的经验计算式.研究表明同一次畦灌过程中地表储水形状系数并非恒定值,而是随灌水时间和水流推进距离等因素变化的.结合已有文献资料验证,结果表明采用水量平衡模型模拟畦灌水流运动过程,考虑动态的地表储水形状系数取值,可有效提高模型的计算精度23.32%.同时也表明采用该文所建经验计算式估算畦灌地表储水形状系数值是可靠的.
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