Abstract
A comprehensive numerical study on flow-induced motions (FIMs) of a deep-draft semi-submersible, a typical multiple cylindrical structure in offshore engineering, was carried out to investigate the energy transformation of the vortex shedding process. In addition, the corner shape effect on the flow characteristics, the hydrodynamic forces, and the FIM responses are presented for a multiple cylindrical structure with various corner shapes (sharp, rounded, and chamfered) under 45○ current incidence. Different energy transformations, hydrodynamic characteristics, and FIM responses were observed due to the slight variation of the corner shape. The galloping at 45○ incidence for a square section shape column was observed when the corner shape modified as a chamfered corner. A “re-attached vortex shedding” phenomenon is discovered when the “lock-in” happened for a chamfered corner design. Further insights of the fluid physics into the flow characteristics due to the difference of the corner shape are revealed. In addition, the energy transformation and the mechanism for reducing the hydrodynamic forces and the FIM responses are analyzed.
Original language | English |
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Article number | 027105 |
Number of pages | 17 |
Journal | Physics of Fluids |
Volume | 32 |
Issue number | 2 |
DOIs | |
Publication status | Published - 25 Feb 2020 |
Keywords
- flow-induced motions (FIM)
- vortex-induced motions (VIM)
- corner shapes
- energy transformation
- galloping structures
- vortex shedding