Seakeeping Properties of Towing a Massive and Asymmetric Caisson

Michimae, Takeru; Sanuki, Hiroshi; Imamura, Tadashi; Sakai, Katsuhiro; Koga, Daisaburo; Niwa, Tsuyoshi; Itou, Yuushi

doi:10.2208/kaigan.74.i_1051

Cited by 3 publications

(1 citation statement)

References 2 publications

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“…From numerical simulations based on the source technique, Ishimi et al [9] showed that footings reduce the heave and pitch (rotational motion around the wave crest direction). Michimae et al [10] experimentally revealed that the pitch of a floating long caisson with a non-rectangular shape is small in the presence of footings compared with caissons without footings. However, there is no study that has varied the footing length except for Nagasawa et al [8], and their investigation was limited to the influence on the heave.…”

Section: Introductionmentioning

confidence: 99%

Motion of Floating Caisson with Extended Bottom Slab under Regular and Irregular Waves

Nakamura

Nagayama

Cho

et al. 2021

JMSE

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Floating caissons may oscillate primarily due to ocean waves during towing operations. Reducing the oscillation based on the extension part (footing) of the bottom slab of the caissons can efficiently increase the safety of towing maneuvers. However, the influence of the footing length on the motion of floating caissons has not been adequately studied. This study investigates this topic through hydraulic model experiments and numerical simulations. Experimental results for regular waves show that the rotational motion (pitch) of the caisson around the wave crest direction increases owing to resonance. This suggests that the pitch could be reduced by designing caissons, such that resonance may be prevented along the footing length. In the numerical simulations of irregular waves, the Fourier amplitudes of the heave and pitch show that the footings amplify their low-frequency components and reduce their high-frequency components. Furthermore, the significant total amplitudes of the heave and pitch show a different trend from that of the regular waves observed in the hydraulic model experiments. This suggests that it is essential to examine the motion of a caisson under irregular waves when assessing the effect of footings in an actual marine environment.

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Section: Introductionmentioning

confidence: 99%