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Research on Application of Numerical Simulation of Sea Water to Ocean Engineering

海水数值模拟在海洋工程中的应用研究

基本信息

批准号：
07505025
负责人：
FUJINO Masataka
金额：
$ 9.73万
依托单位：
University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1997
项目状态：
已结题

项目摘要

In order to validate numerical simulation program of sea water movement, oceanophysical measurement of temperature and salinity of sea water around an existing large floating structure (which is called Mega-Float structure : 300m in length, 60m in breadth, 2m in depth and 0.5m in draft) moored off Oppama in Tokyo Bay was started in August 1996 and is still now underway.The main results of this oceanophysical measurement and numerical experiment are as follows(1) Mega-Float structure does not produce any remarkable oceanophysical effect on the surrounding sea water. The variation of water temperature and salinity in the close vicinity of Mega-Float structure are mainly subject to the tidal current caused in the mooring site of Mega-Float structure.(2) In summer of 1996 and 1997, anomalous sudden fall of sea water temperature and rise of salinity were observed several times along the west coast of Tokyo Bay, i.e.off Oppama and off Negishi. These phenomena occurred in a common situation that typhoons stayd for a while in the western part of Japan or passed though it, and consequently, relative strong blow of southwesterly wind lasted for a few days in Tokyo Bay. On the occasion of the typhoon NO.12 in the middle of August 1996, salinity increase was about 3.5psu and temperature drop was about 6ﾟC.As a result of numerical simulation, it was found that these unusual temperature drop and salinity increase were induced by the so-called coastal up-welling caused by continuous blow of southwester in Tokyo Bay.Besides, numerical simulation can provide us with a very useful tool of predicting the sea water movement in a small sea area such as Mega-Float structure with accuracy enough for practical use.

为验证海水运动数值模拟程序的有效性，于1996年8月对东京湾Oppama附近已有的大型浮式结构物(长300m、宽60m、深2m、吃水0.5m)周围的海水温度和盐度进行了海洋物理测量，目前仍在进行中。Mega-Float结构附近水温和盐度的变化主要受Mega-Float结构系泊处的潮流影响。(2)1996年和1997年夏季，东京湾西海岸，即大玉和Negishi外，多次出现海水温度骤降和盐度升高的异常现象。这些现象发生在台风在日本西部停留或过境的普遍情况下，因此东京湾持续了几天较强的西南风。在1996年8月中旬第12号台风来临时，盐度升高约3.5psu，温降约6ﾟC。数值模拟结果表明，这些异常的温降和盐度升高是由东京湾西南风持续吹袭引起的所谓沿岸上升流引起的。此外，数值模拟可以为预报像巨型浮标结构这样的小海域的海水运动提供一个非常有用的工具，具有足够的精度。