定常流中の係留浮体の動的応答

概要

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Waters pumped up from oceans have been em-ployed for Ocean Thermal Energy Systems for several years. Now attention is being given to the utilization of the nutrition value of the unpolluted waters from deep seas. For effective exploitation of deep waters for agricultural purposes or for industries dealing with marine products, it is important to uplift the water at minimum cost. One of the economical meth-ods of uplifting the deep-sea water would be to use soft (flexible) pipes held at their tops using either floats or buoyancy-type platforms. A basic experimental study on the behavior of a moored-float, whose proto-type corresponds to a large-scale floating structure like a tension-leg-platform, under the actions of cur-rent flow has been conducted. The response character-istics due to fluid drag and lift forces were investi-gated. The models were placed in a circulating water channel under unidirectional current flow. The re-sponse vibrations were recorded and analyzed. The results indicate that in-line components of responses increase with flow velocity due to higher fluid drag forces. The variation in the cross-flow components is much more complex and is influenced by eddies and other forms of turbulence. Also, the vortex-induced vibration involves a feedback mechanism in which vi-bration of the model and the vortex formation are coupled to each other.
鹿児島大学の論文
1998-09-30