Water wave interaction with surface-piercing porous cylinders using the null-field integral equations

Chen, Jeng‐Tzong; Lin, Yi-Jhou; Lee, Y.T.; Wu, C. F. J.

doi:10.1016/j.oceaneng.2010.11.006

Cited by 33 publications

(5 citation statements)

References 17 publications

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“…Zhong and Wang (2006) developed a theoretical model to study the interaction of solitary waves with a concentric porous cylinder system. Chen et al (2011) used the null-field integral formulation to study the near trapping phenomenon by an array of porous cylinders and assessed the porous effects and the disorder of the layout on the near trapping phenomenon. Mandal et al (2013) applied the Fourier-Bessel series expansion method in conjunction with the least square approximation to investigate the wave interaction with an exterior porous and flexible thin cylinder protecting an inner impermeable cylinder.…”

Section: Introductionmentioning

confidence: 99%

Analytical modeling of water wave interaction with a bottom-mounted surface-piercing porous cylinder in front of a vertical wall

Cong

Bai

Teng

2019

Journal of Fluids and Structures

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The interaction of water wave with a bottom-mounted surface-piercing porous cylinder near a rigid vertical wall is investigated by an analytical model newly developed in the present work within the context of linear potential flow theory. The image principle is used to transfer the original problem in bounded water into the equivalent problem of wave interaction with two symmetrical porous cylinders in open seas in the presence of bi-directional incident waves. The velocity potential is analytically derived by means of the eigenfunction expansion along with the matching technique. Furthermore, a new alternative method for the evaluation of wave force is developed via the application of the Haskind-Hanaoka relation to a porous structure. In this method, an auxiliary radiation potential is introduced to replace the diffraction potential for the calculation of wave force. The auxiliary radiation potential used here is due to the oscillation of a porous cylinder in front of a wall. The image principle is used again to search the solution of the wave radiation problem in bounded water and the original radiation problem is then transferred to that due to two porous cylinders undergoing in-phase or out-of-phase motions in open seas. After the validation of the 2 developed model, detailed parametric study is carried out. The porosity of the cylinder, incident wave heading and spacing between the cylinder and the wall are systematically adjusted to investigate their effects on the wave force as well as the wave elevation. The extension of our model to the case of a cylinder array in front of a wall has also been performed, and the associated phenomenon has been explored.

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Section: Introductionmentioning

confidence: 99%

Analytical modeling of water wave interaction with a bottom-mounted surface-piercing porous cylinder in front of a vertical wall

Cong

Bai

Teng

2019

Journal of Fluids and Structures

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“…The occurrence of these small peaks is explained as below. The continuity of the fluid velocity between the inner and the outer regions is fulfilled by Equation (5). Based on Equation ( 5), the normal fluid velocity across the porous shell can be expressed as…”

Section: Numerical Results and Discussionmentioning

confidence: 99%

“…Linear relations between the pressure drop across the porous geometry and the traversing velocity were derived by researchers, e.g., by using Darcy's law [1] or by using the convection neglected and porous effect modelled Euler equation [2]. The linear laws were adopted in many studies in assessing the functional performance of porous breakwaters of different types, such as vertical or submerged horizontal porous plates, perforated caissons, and porous columns [3][4][5][6][7][8]. Based on a linear resistance law, Zhao et al [9] examined the various hydrodynamic identities for porous structures.…”

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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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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“…To avoid the near-trapping phenomenon at a certain frequency, Duclos and Clement [13] studied a disorder parameter to randomly displace the array of unevenly-spaced vertical cylinders from a regular array. 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.…”

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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Water wave interaction with surface-piercing porous cylinders using the null-field integral equations

Cited by 33 publications

References 17 publications

Analytical modeling of water wave interaction with a bottom-mounted surface-piercing porous cylinder in front of a vertical wall

Analytical modeling of water wave interaction with a bottom-mounted surface-piercing porous cylinder in front of a vertical wall

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

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

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