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http://dx.doi.org/10.5574/KSOE.2017.31.3.196

Study on Dynamic Stability of Cylindrical Structure in Waves  

Jang, Min-Suk (Ocean Science and Technology School, Korea Maritime and Ocean University)
Jo, Hyo-Jae (Division of Naval Architecture and Ocean Systems Engineering, Korea Maritime and Ocean University)
Hwang, Jae-Hyuk (Division of Naval Architecture and Ocean Systems Engineering, Korea Maritime and Ocean University)
Kim, Jae-Heui (Division of Naval Architecture and Ocean Systems Engineering, Korea Maritime and Ocean University)
Lee, Byeong-Seong (Research Institute of Medium and Small Ship-Building)
Park, Chung-Hwan (Research Institute of Medium and Small Ship-Building)
Publication Information
Journal of Ocean Engineering and Technology / v.31, no.3, 2017 , pp. 196-201 More about this Journal
Abstract
A cylindrical structure has a very long period of heave and pitch motion response in ocean waves. To obtain the dynamic stability of a cylindrical structure, it is necessary to obtain the suitable metacentric height (GM). However, in a structure with sufficient metacentric height, Mathieu instability can occur if the natural frequency of the heave motion is double the natural frequency of the roll and pitch motion. This study carried out numerical calculations and experiments for vertical-axis wind turbines with cylindrical floaters, which had three different centers of gravity. In the regular wave experiment, the divergence of the structure motion without yaw was observed when the natural frequency of the heave motion was double the natural frequency of the roll and pitch motion. In the irregular wave experiment, the motion spectra of the structures with the different centers of gravity were compared, and one was very high when the natural frequency of the heave motion was double the natural frequency of the roll and pitch motion.
Keywords
Cylindrical structure; Mathieu instability; Metacentric height; Dynamic stability; Vertical axis wind turbine;
Citations & Related Records
Times Cited By KSCI : 2  (Citation Analysis)
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1 Koo, B.J., Kim, M.H., Randall, R.E., 2004. Mathieu Instability of a Spar Platform with Mooring and Risers. Ocean Engineering, 31(7), 2175-2208.   DOI
2 Oh, T.W., 2003. An Experimental Study for the Dynamic Behaviour of Spar. M.Sc Thesis, Korea Maritime and Ocean University, Republic of Korea.
3 Park, C.I., 2013. Stability Analysis of Mathieu Equation by Floquet Theory and Perturbation Method. Transactions of the Korean Society for Noise and Vibration Engineering, 23(8), 734-741.   DOI
4 Rho, J.B., Choi, H.S., 2005. The Effect of Damping Plate on Mathieu-type Instability of Spar Platform. Journal of the Society of Naval Architects of Korea, 42(2), 124-128.   DOI
5 Rho, J.B., Choi, H.S., Shin, H.S., Park, I.K., 2005. A Study on Mathieu-type Instability of Conventional Spar Platform in Regular Waves. International Journal of Offshore and Polar Engineering, 15(2), 104-108.
6 Hong, Y.P., Lee, D.Y., Choi, Y.H., Hong, S., Kim, S.E., 2005. An Experimental Study on the Extreme Motion Responses of a Spar Platform in the Heave Resonant Waves. In The Fifteenth International Offshore and Polar Engineering Conference. International Society of Offshore and Polar Engineers.