基于非结构网格的长江口横沙东滩新陆域数值模拟

为探讨长江口横沙东滩新陆域不同成陆方案对长江口北槽水动力条件的影响,基于CJK3DWEM模型,建立了新陆域数学模型,划分计算水域三角形单元138 281个,网格边长平均约150.0 m。计算结果表明:横沙东滩新陆域形成后,北港上断面、南槽下断面落潮分流比略有减小,分流比变化均在1.00%以内;南港河段、北槽中上段涨落急流速不同程度增加,增加幅度为5~15 cm/s;北槽下段涨落急流速略有减小,减小幅度为5~10 cm/s;北港沿程落急流速有不同程度减小,减小幅度为5 cm/s左右;工程区北侧和南侧高潮位降低,低潮位变化相对较小,原因在于圈围工程主要布置在横沙东滩高程-5.0 m以上浅滩区域,圈围后明显阻隔了涨潮漫滩流。

Unstructured grid-based numerical simulation on Hengsha East Shoal of Yangtze River Estuary

In order to explore the impacts from various land forming schemes for the new terrestrial area of Hengsha East Shoal at the Yangtze River Estuary on the hydrodynamic condition of the north channel of the Yangtze River Estuary， a mathematical model of the new terrestrial is established based on the CJK3D-WEM model， and then the water area therein is calculated and divided into 138 281 triangular elements with the average grid side-length of about 150 m. The calculation result shows that after the formation of the new terrestrial area， the ebb flow diversion ratios of both the upstream cross-section of the north channel and the downstream cross-section of the south passage are slightly decreased with both the variations of the diversion ratios within 1%， while the tidal and ebb rapid flow rates of the river channel of the south passage and the mid-upstream section of the north channel are increased to various extents with the increasing amplitude of 5~15 cm/s. Both the tidal and the ebb rapid flow rates of the downstream section of the north channel are slightly decreased with the decreasing amplitude of 5~10 cm/s. The ebb rapid flow rate along the channel of the north channel is decreased to various extents with the decreasing amplitude of 5 cm/s. The high tidal levels of both the north side and the south side of the project area are lowered and the variations of the low tidal levels are relatively small， for which the causation is that the encircled reclamation project is mainly arranged on the shoal area of -5 m above Hengsha East Shoal， thus the tidal flooding current is to be obviously obstructed after the completion of the encircled reclamation.