ピッチング加振により励起される水平円筒容器内スロッシングと多孔板の減衰効果

Abstract

Floating Production Storage and Offloading (FPSO) system is now attracting big attention which can develop the natural gas fields under the sea. This paper is related to dynamical design of FPSO system, specially focused on the free surface elevation in the horizontal cylindrical and axisymmetric liquid vessel with end caps induced by the wave. The purposes of this research are to model the sloshing in the horizontal cylindrical container under pitching excitation, and to investigate the damping effect of punching plates. First, the theory on the wave height and the resonant frequency in a horizontal cylinder subjected to pitch external excitation is developed. Then, the theory which is capable of taking account of the damping effect of punching plates installed in the cylindrical vessel is described. Finally, the experimental data of resonant wave height up to the third mode are compared to the theoretically derived results. As a result, we can say that the sloshing theory in a horizontal cylindrical container we built in this paper can demonstrate the wave height response qualitatively and quantitatively especially near the first resonance frequency, and that the damping effect of punching plate can be modeled by using the revised resistance coefficient and the velocity of a flowing fluid.