人工岛群对弱潮区海岸动力影响的叠加效应分析

Analysis of Superposition Influence Effect of Artificial Island Group on Coastal Dynamics in a Weak Tidal Zone

为科学评价人工岛群对周边海岸动力产生的影响,基于MIKE21数值模拟软件建立秦皇岛金梦海湾潮流模型和波浪模型,运用验证合理的模型计算人工岛(群)作用下的潮流场和波浪场。在对金梦海湾已建人工岛群影响下的区域动力过程特征分析的基础上,选取合适分析点研究人工岛间的相互作用。研究表明,由于莲花岛与海螺岛的阻流、导流和分流作用,潮流在海螺岛与岸线之间形成较大范围弱环流区,流速几乎为零,并在莲花岛与海螺岛形成的口门处及人工岛群外侧海域形成流速显著增加区域。这3处区域流场受人工岛群影响最大,其中海螺岛起到控制性作用。在人工岛群共同作用下金梦海湾潮流的变化不是各单一人工岛作用下变化的线性叠加,而有效波高受人工岛间相互作用的影响是线性的。人工岛群对金梦海湾起到很好的消浪效果,但却大大削弱了近岸区域的潮流动力。

Focused on the influence of artificial island group on surrounding wa ve-current coupled hydrodynamics,a tidal current model and a wave model for Jingmeng Bay in Qinhuangdao,which had been well calibrated,were established to calculate the surrounding current and wave with the software MIKE21.Based on the analysis of hydrodynamic responses to artificial island group,some measurement points were selected to study the interaction between artificial islands.It can be founded that tidal current,due to resistance,guide and diversion functions by artificial islands,formed a large area of weak circulation between the Conch Island and shoreline,but it increased significantly in the inlet between the Lotus Island and Conch Island as well as the outer sea area of artificial island group.Current fields located in the three mentioned areas were largely affected by artificial islands,of which the Conch Island plays a controlling role.The changes of tidal current velocity,caused by artificial island group,were not satisfied with linear superposition of differences induced by each artificial island.However,the group influence on wave field is linearly summed by individual artificial island influence.The construction of artificial island group has advantageous in wave attenuation,but greatly weakens the tidal current in near-shore area.