中文摘要：

黄河大柳树-沙坡头河段位于宁夏境内，是由5个弯道组成的连续弯道，具有较为复杂的地形特征．利用所建立的修正的平面二维RNGκ-ε紊流泥沙数学模型，对该河段水流运动及泥沙运移进行了平面二维数值模拟研究．采用全沙模型，考虑不同粒径组悬移质和推移质运移对河床演变的影响．通过数值模拟结果与实测结果的对比分析，表明该模型能够模拟具有连续弯道的天然河流水流运动及泥沙运移过程；建立了一种关于泥沙数学模型中水流模块和泥沙模块的半耦合式算法，其计算量比耦合式算法较小，但计算精度比分离式算法较高．

英文摘要：

Being located in Ningxia Hui Autonomous Region and composed of five bends, the Dalushu-Shapotou reach of the Yellow River has complex topography. The developed and modified two dimensional RNG k-e turbulence closure model is used to simulate the flow and sediment transport in the reach. Total load mathematical model is adopted, in which the bed deformations caused by various fractions of the particle size of suspended load and bed load are considered. The numerical result and the measured data are compared and analyzed, indicating that the model can be used to simulate flow and sediment transport in natural rivers with continuous bends. In addition, on the basis of the coupled and separated algorithms about flow and sediment modules, a semi-coupled algorithm is developed, which needs less calculation time than the coupled algorithm, and is more accurate than the separate algorithm.