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

为了评估巨型浮式海洋结构物对周围海水的环境影响，开发了数值模拟程序。然后，假设一个长6公里、宽2公里的假想HFO停泊在一个简化的模型海湾中心，即一个40公里×20公里的长方形海湾，进行了数值试验。HFOS的预期环境效应是通过阻断太阳射线、蒸发和降水对海面的入侵，以及防止风应力的出现等。数值试验的主要结果如下：(1)HFOS周围水温的不均匀分布引起的海水运动是不可忽略的。因此，从加强HFO周围海水交换的角度来看，HFO可能会产生积极的影响。(2)这种海水运动不仅发生在海湾的最外层，也发生在底层。(3)这种海水运动不仅限于HFO附近，而且可能扩散到远离HFO的地方。(4)根据对HFO下大量海水颗粒的跟踪结果发现，夏季海水的扩散倾向于比冬季更远。

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.