Study on the Basic Design Method for Deployment of a Deep-Sea Buoyancy Engine Module

A deep-sea test module was developed for the operation test of a buoyancy engine at deep-sea, which is one of the key elements of underwater gliders. When a deep-sea module is dropped in water, it is dropped with a weight with greater buoyancy than the deep-sea test module. The resistance coefficient of the test module must be determined to predict the dropping speed in water when the deep-sea test module is deployed and estimate a sufficient length between the weight and the test module (buoyancy engine). The test module may collide with the weight or the seabed if the speed of descent of the weight is too fast. In addition, the module may collide with the weight if the length of the rope connecting the weight and the test module is not long enough. Therefore, it is important to determine the resistance coefficient of the module to predict the descent velocity when dropping it. This study examined the resistance coefficient of the test module in relation to the flow velocity. The results confirmed that the length of the rope between the weight and the deep-sea test module was sufficient for the purpose.