插板透水丁坝透水孔优化方案数值模拟

Numerical simulation on optimization scheme of permeable holeof permeable sheet piling spur dike

针对插板透水丁坝透水孔孔数和布置方式对丁坝作用区水流特性和冲淤变化影响的问题,采用CCHE2D水沙数学模型对塔里木河干流其满河段实体模型水槽插板透水丁坝区进行二维水流数值模拟,分析不同透水孔数和不同布置方式对河槽断面流速分布、水位及河床切应力的影响规律,寻求插板透水丁坝透水孔优化方案。结果表明:在来流量、透空率等因素不变条件下,插板透水丁坝透水孔数越多,流速均匀性越好,丁坝下游河床切应力呈减小趋势。当透水孔数达到4孔时,丁坝上游、下游水位、流速和河床切应力变化趋势均趋于稳定,为最佳的透水孔优化方案。研究成果为进一步研究插板透水丁坝区水流特性与缓流促淤效果奠定理论基础。

Aimed at the problems about that permeable hole number and permeable hole layout of Permeable Sheet Piling Spur Dike(PSPSD) affect the flow characteristic and the changes of scouring and deposition at spur dike area. CCHE2 D flow simulation mathematical model is adopted,two dimensional flow numerical simulation is carried out for the permeable spur dike area of the physical model of the Qiman reach of the Tarim River main stream,the influences law of cross section velocity,water level,and river bed shear stress of different permeable hole count and layout are analyzed. The optimization scheme of permeable hole for the PSPSD is sought.The results show that the more number of permeable hole of the PSPSD,the smaller the flow velocity upstream and downstream of the spur dike. bed shear stress showed a decrease trend downstream of the spur dike. When the number of permeable holes reaches 4,the water level,flow velocity,and river bed shear stress change trend become stable upstream and downstream of the spur dike. The optimization scheme for the permeable spur dike with the best effect of flow retardation is that the number of permeable hole is 4. The research results lay a theoretical foundation for the further study on the flow characteristic and effect of flow retardation and deposition promotion at spur dike area.