水位流速耦合演算模型研究

Study of water-level and flow-velocity coupled routing model

河道防洪,水位和流速是重要的预报特征量。目前对于缺乏流量观测资料和没有稳定水位流量关系线的河道,几乎还没有实用、有效和具有通用性的水位与流速双变量预报模型。以水流质量和力的平衡方程为基础,根据因次分析方法,提出摩阻的导数表达结构,并差分形成水位流速双变量耦合演算模型。通过钱塘江、赣江和桂江3个流域中4个河段的模拟检验,取得了较好的结果,率定期和检验期的确定性系数都大于0.7。初步证明了双变量耦合演算模型结构的合理性和模拟实际河道水流的有效性。

Water level and flow velocity are two critical factors for flood control and forecasting. However,to our knowledge,there are few universal models that have been able to simulate water level and flow velocity effectively especially in the river channels without observed discharge data or stable stage-discharge relationship. In this study,the derivative expression of the friction is proposed using dimensional analysis based on water balance equation and force equilibrium equation. Then,the bi-variable（ water level and flow velocity） coupling model is established by solving the derived differential equation. The developed model is tested in four river reaches in the Qiantang River,the Ganjiang River,and the Guijiang River. Our results indicate that the model can provide good simulations of water level in the study area（ with coefficient of determination larger than 0. 7 during both calibration and validation processes）.This study also confirm the rationality of the model structure and its effectiveness in simulating the river flow.