Numerical Experiment of Sea-water Exchange around Huge Floating Offshore Structure

为了评价大型海洋浮式结构物（HFOS）对近岸海域的环境影响，开发了数值模拟程序。然后，在一个40 km × 20 km的简化模型海湾（即矩形海湾）的中心，停泊一个长6 km、宽2km的假想HFOS，进行了数值试验。HFOS的预期环境效应主要表现在：（1）HFOS周围水温分布不均匀引起的海水运动具有不可忽略的量级;因此，从加强HFOS周围海水交换的角度来看，可以说HFOS可能产生积极的效果。（2）这种海水运动不仅发生在海湾的最外层，而且发生在底层。（3）这种海水运动不仅限于HFOS附近，而且可能向远离HFOS的地方扩散。(4)根据HFOS下对多个海水粒子的跟踪结果发现，夏季海水扩散比冬季有进一步扩散的趋势。

In order to estimate environmental effects of huge floating offshore structures (HFOS) on the surroundig sea water, numerical simulation program was developed. And then, numerical experiments were carried out assuming that an imaginary HFOS of 6km in length and 2km in width was moored in the center of a simplified model bay, i.e.a rectanglar bay of 40kmx20km. Expected environmental effects of HFOS are caused by interrupting the intrusion of solar ray, evaporation and precipitation on the sea surface, and by preventing appearance of wind stress, and so on.The main results of numerical experiments are as follow :(1) Sea water movement induced by ununiformed distribution of water temperature around HFOS is of unnegligible order. Hence, from the viewpoint of enhancing sea water exchange around HFOS,it can be said that HFOS may produce affirmative effects.(2)This sea water movement is brought about not only in the outermost layr in a bay but also in the bottom layr(3) This sea water movement is not restricted in the close vicinity of HFOS,but may spread far from HFOS.(4) According to the results of tracking a number of sea water particles under HFOS,it is found that sea water tends to spread further in summer than in winter.