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

为了控制阿里亚克海底层出现的缺氧水，本研究开发了两套海水交换系统。一种是利用阿里亚克海域上层与底层流速的自然差异所产生的低气压。另一种是螺杆系统。1)利用三种管径(φ=0.2m、0.3m和0.4m)的较低压力进行抽水试验。在本实验中，当管道上侧的接近速度达到2.6 cm/S或以上时，开始观测抽水速度。2)采用下引水管(φ：0.6m×5m)对模型的应用水平进行测试，试验结果表明，模型的接近速度和下侧抽水速度的最大速率分别为38.2 cm/S和35.4 cm/S。由此认为，管道内的泵送速度主要受有效波高的影响，而不受管道上部接近速度的影响。3)新研制了一套带有螺杆系统的仪器，用于将地表水流输送到底部。根据由两种螺杆组成的仪器(φ：0.3m上端和φ：0.1m底端)的测试结果，上端的螺杆设计为以0.5m/S的速度移动，而实际的速度为0.3m/S。因此，结果表明，底位螺杆与上位螺杆的运动耦合，使底面水流以18m^3/S的速度流动。

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.