長周期左右揺れをする柱体に働く粘性減衰力について

概要

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Low-frequency viscous damping force acting on a circular cylinder, a lowerhull-section cylinder of a semisubmersible and a flat plate is experimentally investigated. Flow visualization of an oscillating cylinder in combined motion of high-frequency and low-frequency oscillation, reveals that the low-frequency viscous damping force is caused by the deformation of the shedding vortices in each swing of the high-frequency oscillation by the low-frequency oscillation. On the basis of experimental results, a prediction method of the damping force is proposed. In the method, an experimental drag coefficient, which depends on the shape of models and the Keulegan-Carpenter, is needed. The drag coefficient is determined by exper imental results for each cylinder. The memory effect on the drag coefficient due to vortices created in the previous swing is discussed.
社団法人日本船舶海洋工学会の論文
1990-03-25