长江下游二维浅水非恒定流数值模拟

Numerical simulation of usteady 2-D shallow water flow of the lower Yangtze River

长江下游河段水流受径流和海域潮汐双重作用,水流动力机制复杂,此外,长江下游河道形式多为分汊河道,河床边界蜿蜒曲折。作为前期工作的进一步拓展,本文将基于非结构三角网格体系的非恒定浅水二维水流数学模型用于研究长江下游水流变化过程。文中分别选取了长江下游和畅洲河段和福姜沙河段进行了数学模拟试验,通过潮位过程、断面流速流向及流速过程比较分析来检验本文模型对长江下游水流变化过程的适用性,计算结果与实测值对比表明:通过对模型参数进行率定,本文模型的计算潮位过程和流速流向值与实测值吻合较好,显示了本文模型能够很好地应用于长江下游水流变化过程研究。

Flow in the lower Yangtze is affected by river inflow and tidal current that has a complicated dynamics and the river is often branched and shows wandering water fronts. As an extension of the previous study the present work does numerical simulation of unsteady two-dimensional shallow-water flow on unstructured triangular grids to study the flow variations in the lower Yangtze. Hechangzhou and Fujiangsha reaches were simulated for verification of the model through comparison of tide levels and flow velocities. Results show that with the model parameters calibrated, the calculated variation in tidal level and flow velocity agree well with the measurements.