The transient responses in the fixed and free-heaving moonpools under the conditions of linear and nonlinear gap resonance are investigated. A two-dimensional numerical model was established using a constrained interpolation profile method-based in-house code. This paper mainly concentrates on the prediction and quantification of the developing and diminishing processes of the free-surface elevation at gap when encountering both the linear gap resonance and quadratic wave excitation (QWE)-driven gap resonance. The parameter analyses with respect to the distance between the barges and barge draft are considered to derive the variation in the response time and damping time. The continuous wavelet transform (CWT) is introduced to investigate the gap resonances for the first time to obtain the transient characteristics' distribution of the free-surface elevation at gap along time and frequency domains. Numerical results demonstrate that the heave motion has changed the developing patterns of both the linear gap resonance and QWE gap resonance in the free-heaving moonpool rather than those in the fixed moonpool. Nevertheless, the impact caused by heave is little as for the diminishment. By introducing a new hyperbolic-function-type amplification function, the development of the gap resonances for the free-heaving moonpool is well predicted. In addition, the opposite tendency is observed for both the response time and damping time between the fixed and free-heaving moonpools when considering from the linear to QWE gap resonances. According to the transient characteristics obtained from the CWT, it is attributed to the different proportions of the free-surface elevation's second-order component between the fixed and free-heaving moonpools at the QWE resonant point. Moreover, the duration of the damping time is found to be greatly influenced by the phase relation between the free-surface elevation at gap and the heave motion of the moonpool from the linear resonant point to the QWE resonant point.
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August 2023
Research Article|
August 18 2023
Transient responses of the linear and nonlinear gap resonances in the fixed and free-heaving moonpools
Special Collection:
Recent Advances in Marine Hydrodynamics
Penglin Jing (荆芃霖)
;
Penglin Jing (荆芃霖)
(Conceptualization, Formal analysis, Software, Writing – original draft, Writing – review & editing)
1
School of Mechatronics Engineering, Harbin Institute of Technology
, Harbin 150001, China
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Guanghua He (何广华)
;
Guanghua He (何广华)
a)
(Conceptualization, Supervision, Writing – review & editing)
1
School of Mechatronics Engineering, Harbin Institute of Technology
, Harbin 150001, China
2
School of Ocean Engineering, Harbin Institute of Technology
, Weihai, Weihai 264209, China
3
Shandong Institute of Shipbuilding Technology
, Weihai 264209, China
a)Author to whom correspondence should be addressed: ghhe@hitwh.edu.cn
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Hassan Ghassemi
;
Hassan Ghassemi
(Validation, Writing – review & editing)
2
School of Ocean Engineering, Harbin Institute of Technology
, Weihai, Weihai 264209, China
4
Department of Maritime Engineering, Amirkabir University of Technology
, Tehran, Iran
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Zhengxiao Luan (栾政晓)
Zhengxiao Luan (栾政晓)
(Data curation, Validation)
1
School of Mechatronics Engineering, Harbin Institute of Technology
, Harbin 150001, China
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a)Author to whom correspondence should be addressed: ghhe@hitwh.edu.cn
Physics of Fluids 35, 087125 (2023)
Article history
Received:
June 10 2023
Accepted:
August 01 2023
Citation
Penglin Jing, Guanghua He, Hassan Ghassemi, Zhengxiao Luan; Transient responses of the linear and nonlinear gap resonances in the fixed and free-heaving moonpools. Physics of Fluids 1 August 2023; 35 (8): 087125. https://doi.org/10.1063/5.0161495
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