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http://dx.doi.org/10.26748/KSOE.2019.028

Experimental Study on Reducing Motion of Circular Cylinder in Currents  

Lim, Jae Hwan (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, Tae Kyung (Division of Naval Architecture and Ocean Systems Engineering, Korea Maritime and Ocean University)
Choi, Yoon Woo (Division of Naval Architecture and Ocean Systems Engineering, Korea Maritime and Ocean University)
Lee, Min Jun (Division of Naval Architecture and Ocean Systems Engineering, Korea Maritime and Ocean University)
Kim, Young Kyu (Division of Naval Architecture and Ocean Systems Engineering, Korea Maritime and Ocean University)
Publication Information
Journal of Ocean Engineering and Technology / v.33, no.4, 2019 , pp. 350-357 More about this Journal
Abstract
The development of marine technology is expected to increase the demand for marine plants because of increasing oil prices. Therefore, there is also expected to be an increase in the demand for cylindrical structures such as URF (umbilical, riser, flowline) structures and spars, which are used operating in various seas. However, a cylindrical structure experiences vortex induced motion (VIM) in a current. In particular, for risers and umbilicals, it is important to identify the characteristics of the VIM because interference between structures can occur. In addition, various studies have been conducted to reduce VIM because it is the cause of fatigue damage to structures. The helical strake, which was developed for VIM reduction, has an excellent VIM reduction performance, but is difficult to install on structures and has a negative effect on heave motion. Therefore, the purpose of this study was to supplement the shortcomings of the helical strake and develop a high-performance reduction device. In the reduction device developed in this study, a string is placed around the structure inside the flow, causing vibration. The vibration of this string causes a small turbulence in the flow field, reducing the VIM effect on the structure. Finally, in this study, the 2-DOF motion characteristics of models without a suppression device, models with a helical strake, and models with a string were investigated, and their reduction performances were compared through model tests.
Keywords
Circular cylinder; VIM(Vortex induced motion); String; In-line response; Cross flow response; Model test;
Citations & Related Records
Times Cited By KSCI : 2  (Citation Analysis)
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