甲板昇降式海洋掘削台の脚に加わる流体力について

概要

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In this paper, hydrodynamic forces and wave forces acting on a truss leg of a elevating-deck ocean structure are investigated. The added mass coefficient C_A and the drag coefficient C_<DF> are obtained from forced swaying tests using a leg model. The inertia coefficient C_M and the drag coefficient C_<DW> are obtained by measuring the wave forces acting on the leg model in regular waves. The wave force coefficients C_M and C_<DW> are compared with those of a single vertical circular cylinder. The main conclusions derived from above experimental study can be written as follows: 1) The direction of the motion or the incident wave has no effect on values of C_A and C_<DF> or C_M and C_<DW>. 2) The drag coefficient C_<DF> approaches C_<DO> through values larger than C_<DO> with increasing the amplitude Y_a of the forced-swaying motion, where C_<DO> is the drag coefficient of the leg model in a steady flow. 3) The added mass coefficient C_A increases lineary with Y_a. The ratio of the added mass force to the drag force tends to 0.25 with increasing Y_a. 4) The drag coefficient C_<DW> of the truss leg is very similar to that of a single vertical circular cylinder. 5) The inertia coefficient C_M of the truss leg is more monotonous with increasing the incident wave hight than that of a single vertical circular cylinder. But the quantitative difference between them is small.
社団法人日本船舶海洋工学会の論文
1981-08-27