Model experiments on wave elevation around a four-cylinder structure

Cong, Peiwen; Gou, Ying; Teng, Bin; Kang, Zhuang; Huang, Yifan

doi:10.1016/j.oceaneng.2014.11.031

Cited by 27 publications

(7 citation statements)

References 23 publications

(28 reference statements)

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“…In the previous sections, two different formulations have been proposed for the mean drift wave force on a concentric porous cylinder system. When the near-field formulation is used, the mean drift wave force on the interior column and the exterior shell can be evaluated based on Equations ( 17) and (18), respectively. The force components involved in the far field formulation can be evaluated according to Equations ( 27) and (28), respectively.…”

Section: Numerical Results and Discussionmentioning

confidence: 99%

“…Besides the linear wave force, the nonlinear wave force is also closely relevant to the proper design of offshore structures. The nonlinear hydrodynamic properties related to a vertical column or a column array in open seas has been investigated in some studies spanning from analytical studies to model tests and numerical modelling, such as references [16][17][18][19][20]. However, the nonlinear wave interaction with a vertical column shielded by an exterior porous shell has been rarely investigated so far.…”

Section: Introductionmentioning

confidence: 99%

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Local Enhancements of the Mean Drift Wave Force on a Vertical Column Shielded by an Exterior Thin Porous Shell

Cong

Liu

2020

JMSE

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The wave interaction with a vertical column shielded by an exterior porous shell is studied within the framework of potential flow theory. The structures are fixed rigidly at the sea bottom. The interior cylinder is impermeable, and the exterior shell is slightly porous and thin. Additionally, the exterior shell is assumed to have fine pores, and a linear pressure drop is adopted at the porous geometry. The mean drift wave force on the system is thereby formulated by two alternative ways, based respectively on the direct pressure integration, i.e., the near-field formulation, and the application of the momentum conservation theorem in the fluid domain, i.e., the far-field formulation. The consistency of the two formulations in calculating the mean drift wave force is assessed for the present problem. Numerical results illustrate that the existence of the porous shell can substantially reduce the mean drift wave force on the interior column. It also appears that the far-field formulation consists of a conventional part as well as an additional part caused by the energy dissipation through the porous geometry. The mean drift wave force on the system is dominated by the first part, which resembles that on an impermeable body. Local enhancements of the mean drift wave force are found at some specific wave frequencies at which certain propagation modes of the fluid satisfy a no-flow condition at the porous shell.

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Section: Numerical Results and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Local Enhancements of the Mean Drift Wave Force on a Vertical Column Shielded by an Exterior Thin Porous Shell

Cong

Liu

2020

JMSE

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“…Case 1 (Fig. 4) is for the water wave elevation around a mono-pile foundation (Cong et al 2015). Case 2 ( Fig.…”

Section: Model Validationmentioning

confidence: 99%

Wave-induced seabed residual response and liquefaction around a mono-pile foundation with various embedded depth

et al. 2019

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“…Bai et al [11] used the fully nonlinear boundary element method to analyze the near-trapping phenomenon and proved the third-order excitation of near-trapping in these vertical cylinders. Cong et al [12] showed the first-order and second-order wave elevations around the four vertical cylinders at the near-trapping frequency under different wave directions.…”

Section: Introductionmentioning

confidence: 99%

“…Chen et al [14] investigated the effects on the near-trapping due to the porosity of vertical cylinders and disorder of layout using the null-field integral equations. Evans and Porter [15] and Cong et al [12] studied the effects of wave direction on the wave elevation and the exciting forces in the near-trapping modes of four bottom-mounted-columns; unfortunately, the effects on wave drift forces were not studied. To reduce the wave drift force and improve the hydrodynamic performance of the structures in waves, an optimization scheme is a powerful tool for this type of problem.…”

Section: Introductionmentioning

confidence: 99%

Near-Trapping on a Four-Column Structure and the Reduction of Wave Drift Forces Using Optimized Method

Zhang

Wang

et al. 2020

JMSE

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The near-trapping phenomenon, which can lead to high wave elevations and large wave drift forces, is investigated by a floating four-column structure. To solve this wave-structure interaction problem, a numerical model is established by combining the wave interaction theory with a higher-order boundary element method. Based on this numerical model, behaviors of scattered waves at near-trapping conditions are studied; and the superposition principle of free-surface waves is introduced to understand this near-trapping phenomenon. To avoid the near-trapping phenomenon and protect the structure, a way for rotating the structure to change the wave-approach angle is adopted, and improvements of the wave elevations around the structure and the wave drift forces acting on each column are found. Moreover, a genetic-algorithm-based optimization method is adopted in order to minimize the total wave drift force acting on the whole structure at various wavenumbers by controlling the draft of floating bodies, the wave-approach angle and the separation distance between adjacent floating bodies. With the final optimized parameters, the wave drift forces both on each column and on the whole structure can be significantly reduced. The optimized arrangement obtained from a certain wavenumber can work not only at this target wavenumber but also at a range of wavenumbers.

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Model experiments on wave elevation around a four-cylinder structure

Cited by 27 publications

References 23 publications

Local Enhancements of the Mean Drift Wave Force on a Vertical Column Shielded by an Exterior Thin Porous Shell

Local Enhancements of the Mean Drift Wave Force on a Vertical Column Shielded by an Exterior Thin Porous Shell

Wave-induced seabed residual response and liquefaction around a mono-pile foundation with various embedded depth

Near-Trapping on a Four-Column Structure and the Reduction of Wave Drift Forces Using Optimized Method

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