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DEVELOPMENT OF PREDICTION METHOD FOR ENVIRONMENTAL IMPACTS BY VERY LARGE FLOATING STRUCTURES

超大型漂浮结构对环境影响的预测方法开发

基本信息

批准号：
07555317
负责人：
TABETA Shigeru
金额：
$ 5.95万
依托单位：
YOKOHAMA NATIONAL UNIVERSITY
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

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07555317/
关键词：
VERY LARGE FLOATING STRUCTURE ENVIRONMENTAL IMPACT MULTILEVEL MODEL SINGLARITY DISTRIBUTION METHOD SEPARATE REGION METHOD EXCHANGE OF SEA WATER ECOSYSTEM MODEL 海水流動数値計算

项目摘要

In recent years, the floating system is proposed as an effective measure in constructing ocean airports. The plans of ocean utilization by means of very large floating structures (VLFS) will be increased in the future. Although it is often said that the floating system less affected ocean environment than the reclamation system, it has not been quantitatively proved. On the other hand, it is sometimes pointed out that VLFS may cause bad influence over the eosystem in the dark area below the structure or that the water quality between the floating structure and brakwater may become worse because of the stagnation of sea water. The purpose of this study is to develop numerical methods for the prediction of marine environmental impacts by installing VLFS.Especially, currents and diffusion problems around VLFS and currents and waves between the floating sturcture and breakwater were carefully investigated.At first, 2-dimensional separate region method (2D-SRM) and 3-dimensional singularity distribution method (3D-SDM) were developed as the tools to calculate wave field around the VLFS and dynamic response of the floating body. The developed 3D-SDM is applicable to the calculations of both frequency and time domain, considering the mutual interaction between multiple floating bodies with arbitrary shape. The developed 2D-SRM is applicable to the calculations including the effects of hydroelastic response of the floating body and interaction between the structure and breakwater. Next, a multilevel model has been modified to include the effects of VLFS for currents and diffusion problem. This model can calculate the density variation and can also evaluate the exchange ratio of sea water. For investigating the influences on ecosystem by VLFS,a simple 1-dimensional model in the vertical direction was deeloped and applied to the preliminary investigation.

近年来，漂浮系统被提出作为建设海洋机场的一种有效措施。未来将增加利用超大型浮式结构物(VLFS)进行海洋利用的计划。虽然人们常说漂浮系统比填海系统对海洋环境的影响要小，但这一点还没有得到定量的证明。另一方面，有时也会指出，VLFS可能会对建筑物下方暗区的生态系统造成不良影响，或者由于海水的滞留，浮式建筑物与刹车水之间的水质可能会变得更差。本研究旨在建立超大型浮体浮体对海洋环境影响的数值计算方法，特别是对浮体浮体周围的水流和扩散问题以及浮式结构物与防波堤之间的流和波浪问题进行了深入的研究。首先，发展了二维离散区域法(2D-SRM)和三维奇点分布法(3D-SDM)作为计算浮体浮体动力响应的工具。所开发的3D-SDM既适用于频域计算，也适用于时间域计算，考虑了任意形状浮体之间的相互作用。所开发的2D-SRM可用于浮体水弹性响应以及结构与防波堤相互作用的计算。接下来，对多层模型进行了修改，以考虑VLFS对电流和扩散问题的影响。该模型可以计算海水的密度变化，也可以估算海水的交换率。为了研究VLFS对生态系统的影响，开发了一个简单的垂直方向一维模型，并将其应用于初步调查。