大型海洋倾倒区悬浮物迁移扩散的数值模拟

Numerical simulation of transport and dispersion of suspended matter due to dredged sediment disposal into large marine dumping area

以温州港进港航道疏浚工程的某大型海洋倾倒区为例,在验证良好的区域二维潮流数学模型的基础上,结合均匀分布函数设置的随机模型建立悬浮物迁移扩散模型,模拟该倾倒区附近海域在单船抛卸工况下产生的悬浮物质量浓度增量分布变化过程,得到周围海域悬浮物最大质量浓度增量分布情况.通过与相同情况下采用固定点源设置的模型计算结果进行比较,讨论对大型倾倒区采用随机点源设置的合理性及必要性.探讨随机点源设置与倾倒区尺度的关系,认为在瓯江口以外海域,对面积>1 km2的倾倒区作业期间悬浮物迁移扩散进行数值模拟,有必要采用随机点源设置.

Based on a well-verified two-dimensional mathematical model for tidal current,a numerical model combined with a stochastic model using the uniform distribution function was developed to study the transport and dispersion of suspended matter from a large marine dumping area for the project of dredging waterway into Wenzhou Harbor.The temporal and spatial distributions of the concentration of suspended matter disposed by a single workboat were simulated near the dumping area.The maximum increments of the suspended matter concentration were obtained.The stochastic point-source model showed more reasonable predictions compared with the results obtained from the fixed point-source model.The necessity of using the stochastic point-source model was discussed based on the scale of the marine dumping area.When the dumping area is more than 1 km2,the stochastic point-source approach should be used to simulate the transport and dispersion of suspended matter in the sea area beyond the Oujiang Estuary.