DEVELOPMENT OF CONTROL TECHNOLOGY OF THE ANOXIC WATER IN ARIAKE SEA.

为了控制有明海底层缺氧水的产生，本研究开发了两套海水交换系统。一种是利用有明海自然形成的上下层流速差所产生的低压;（1）利用低压进行抽水试验，用φ=0.2m、0.3m、0.4m三种管径的管子进行抽水试验。2）采用φ 0.6mx5m的暗管对模型的应用水平进行了试验，试验结果表明，模型的最大接近流速和最大抽汲流速分别为38.2cm/s和35.4cm/s;因此，认为管道内的泵送速度主要受有效波高的影响，而不受管道上部的接近速度的影响。由于试验内容较新，需要进一步的试验来揭示泵送速度与有效波高的关系; 3）为了将表面流向底侧输送，设计了一种新型的带螺旋系统的试验装置，通过两种螺旋系统的试验结果表明，该试验装置的有效波高随泵送速度的增加而增加，但其有效波高随泵送速度的增加而增加（φ：上部0.3 m，φ：0.1 m（底部位置），上部位置的螺杆设计为以0.5 m/s的速度移动，但实际速度为0.3 m/s。因此，可以确定，底部位置螺杆的运动与上部位置螺杆的运动相结合，使得底层的流量为18 m^3/s。

To control the anoxic water occurring in the bottom layer of Ariake Sea, two seawater exchange systems were developed in this study. One is to utilize the lower pressure caused by the different velocity between upper layer and bottom naturally in Ariake Sea. Another is screw system.1)The pumping test utilized the lower pressure carried out with pipes of three types of diameter (φ=0.2m, 0.3m and 0.4m). In this experiment, the pumping velocity was started to observe, after the approaching velocity at the upper side of pipes reached at 2.6cm/s or more.2)The application level of the model was tested using the underdrainage pipe (φ:0.6m x 5m).At the result of the test, it was observed that the maximum rates of the approaching velocity and the pumping velocity toward bottom side were 38.2cm/s and 35.4cm/s, respectively. Thus, it was considered that the pumping velocity in the pipe was mainly influenced by the significant wave height, but not by the approaching velocity at the upper site of pipe. As the aspect obtained hi this test was new, further experiments were required to reveal the relationship between the pumping velocity and the significant wave height.3)The instrument with the screw system was newly constructed to transfer the surface flow toward bottom side.As the result of test by the instrument composed of two types of screw (φ:0.3 m at upper site and φ:0.1m at bottom site), the screw of upper site was designed to get moving with the speed of 0.5m/s, however, the actual speed was 0.3m/s. Thus, it was identified that the movement of the bottom site screw coupled with upper site one allowed the flow at bottom layer with the rate of 18m^3/s.