东山湾水动力数值模拟及其纳潮量和水交换周期计算

Hydrodynamic numerical simulation on Dongshan Bay and calculation of its tidal prism and water exchange cycle

东山湾属于半封闭性海湾,水文特性具有一定的代表性。在总结水体交换能力计算方法的基础上,采用对流扩散的水交换模式,建立平面二维数学模型,利用大潮、小潮实测潮位和潮流资料对模型进行了流场的验证,计算了纳潮量,半交换期以及交换率的平面分布。计算得出,大潮和小潮时,纳潮量为9.44×10^8 m^3和5.36×10^8 m^3,半交换期为8.13 d和13.0 d以及交换率的平面分布。整个海湾交换率的平面分布表明:湾口水交换能力最强,湾中部水交换能力良好,而湾顶水交换能力较弱。对东山湾开发利用的过程中,应结合海湾的纳潮量、半交换期以及交换率的分布,合理布置排污口,充分利用海洋自净能力。

Dongshan Bay is a semi-closed bay with a certain representativity of hydrological characteristics.A planar 2-D mathematical model is established herein with the water exchange mode of convection diffusion on the basis of summarizing the methods of calculation of water exchange capacity,and then the flow field is verified for the model by means of the data of both the measured tide levels of spring tide and neap tide and the tidal current,from which the tidal prism,the semi-exchange period and the planar distribution of the exchange rate are calculated.It is obtained from the calculation that the tidal prism therein is 9.44×10^8 m^3 and 5.36×10^8 m^3 with the semi-exchange periods of 8.13 d and 13.0 d respectively during both spring tide and neap tide,while the planar distribution of the exchange rate is obtained as well.The planar distribution of the water exchange rate within the whole bay shows that the water exchange capacity is the strongest at the baymouth and better at the mid-part of the bay,but weaker at the top of the bay.During the development and utilization of Dongshan Bay,the layout of the sewage outfalls therein is necessary to be reasonably made in accordance with the tidal prism,the semi-exchange period and the exchange rate distribution of the bay,so as to fully utilize the marine self-purification capacity therein.