An experimental study of double-row floating breakwaters

Ji, Chunyan; Deng, Xiangyuan; Cheng, Yong

doi:10.1007/s00773-018-0554-2

Cited by 19 publications

(13 citation statements)

References 20 publications

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“…In this section, the numerical model is verified by an experimental model. e experimental model selected for the validation is the study of Ji et al In that study, some experiments were performed on the single-and double-row breakwaters to determine their performance [24]. Figure 4 shows the sketch of the double-row FBWs experimental setup under the regular wave in a wave flume.…”

Section: Validation Of the Numerical Modelmentioning

confidence: 99%

“…ey found that the new FBW has a better performance for the high-period and large-amplitude waves [1]. Ji et al did some experiments about single-and double-row breakwater and then concluded that, in general, the double-row breakwater system has better performance [24]. Ji et al, in an experimental study, analyzed the hydrodynamic behaviors of double-row rectangular pontoon FBW and concluded that double-row FBWs significantly reduce the transmission coefficients [25].…”

Section: Introductionmentioning

confidence: 99%

“…e performance of FBWs in high-wave periods is a problem that has been inadequately investigated. Researchers also concluded that double-row FBWs are efficient in reducing the wave transmission coefficient [1,24,25].…”

Section: Introductionmentioning

confidence: 99%

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Hydrodynamic Performance Improvement of Double-Row Floating Breakwaters by Changing the Cross-Sectional Geometry

Rajabi

Ghassemi

2021

Mathematical Problems in Engineering

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This paper is presented to develop the hydrodynamic performance of double-row floating breakwater (FBW) by changing cross-sectional geometry in the high wave periods. The ANSYS-AQWA software is employed for the present calculations, which is a potential-based boundary element method (BEM). The rectangular moored pontoons in the single- and double-row types are selected, and the results of the wave transmission coefficient and response amplitude operator (RAO) are presented and compared. The numerical results showed good agreement with experimental data at different wavelengths, wave height, and the distance between double-row FBWs. Then, the performance results of FBWs for five shapes (rectangular, π-shaped, plus-shaped, triangular-shaped, and box-shaped) in the wave transmission coefficient, RAO, and mooring line tension are presented and compared to each other. The results showed that the plus-shaped FBW has a better performance in reducing wave transmission than other shapes. In waves with long periods, the performance of π-shaped, triangular-shaped, and box-shaped FBWs is reduced, and the rectangular FBW loses its efficiency. Overall, the plus-shaped FBW has preferable performance regarding RAO response, mooring tension, and wave transmission.

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Section: Validation Of the Numerical Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Hydrodynamic Performance Improvement of Double-Row Floating Breakwaters by Changing the Cross-Sectional Geometry

Rajabi

Ghassemi

2021

Mathematical Problems in Engineering

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“…Williams et al [16] investigated the influence of wave and structural parameters on the wave reflection properties of a pair of cuboid pontoons (Figure 1o). Ji et al [17] compared the hydrodynamic performance of double-row and single-row composite structures composed of two cuboid pontoons at the ends and a mesh cage in the middle (Figure 1p). The results indicated that the eddy losses and moon pool effect made the double-row floating breakwater more effective, and the separation distance between pontoons significantly affect the wave attenuation performance and mooring force.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study on the Hydrodynamic Characteristics of a Double-Row Floating Breakwater Composed of a Pontoon and an Airbag

Cheng

Liu

Zhang

et al. 2021

JMSE

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By adding a cylindrical airbag on the leeward side of a cuboid pontoon, a new-type double-row floating breakwater is designed to improve the wave attenuation performance, and its hydrodynamic characteristics are studied through numerical simulations. First, based on the smoothed particle hydrodynamics (SPH) method, a numerical model used to simulate the interaction between waves and moored floating bodies is built. The fluid motion is governed by the Navier–Stokes equations. The motion of the floating body is computed according to Newton’s second law. The modified dynamic boundary condition is employed to treat the solid boundary. The lumped-mass method is adopted to implement the mooring system. Then, two physical model experiments on waves interaction with cuboid and dual cylindrical floating pontoons are reproduced. By comparing the experimental and numerical wave transmission coefficients, wave reflection coefficients, response amplitude operators and mooring force, the reliability of the numerical model is validated. Finally, the validated numerical model is applied to study the influence of separation distance and wave parameters on the hydrodynamic characteristics of the double-row floating breakwater. The results indicate that the optimal separation distance between pontoon and airbag is 0.75 times the wavelength. At such separation distance and within the concerned 1–4 m wave heights and 4–7 s wave periods, the pontoon-airbag system presents better wave attenuation performance than a single pontoon. This improvement weakens as wave height increases while it strengthens as the wave period increases. In addition, the double-row floating breakwater is more effective in a high-wave regime than in a low-wave regime. In the case of short waves, attention should be paid to the stability and mooring reliability of the seaward pontoon, while in the case of long waves, care needs to be taken of the leeward airbag.

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“…On top of these four categories, three more types of floating breakwaters were introduced in [6]: frame-type, horizontal-plate type, and other types. Special crosssection shapes, such as inverse T-shape [7], π-shape [8], and twin horizontal cylinders [9] were also developed. In addition, floating breakwaters can be interconnected multibody systems.…”

Section: Introductionmentioning

confidence: 99%

Effectiveness of Floating Breakwater in Special Configurations for Protecting Nearshore Infrastructures

Zhang

Magee

2021

JMSE

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This paper investigates the effectiveness of floating breakwaters consisting of two barges (L-shape), three barges (U-shape), four barges (barge frame), and conventional single floating breakwater. The floating breakwaters of different spatial layouts have sheltered internal gaps/moonpools when compared to their conventional counterparts. The motions of these floating breakwaters and their effectiveness in wave transmission and motion reduction of the protected floating bodies are evaluated. The study is conducted based on a subsystem of a floating hydrocarbon storage facility that combines a floating breakwater with two floating tanks, studied previously. Numerical models based on linear potential flow theory are built for these floating breakwaters with and without the floating tanks. The numerical models of the barge frame are validated through laboratory experiments, and the dipole damping lids to reduce the resonant fluid motions in the gaps/moonpools are calibrated with experimental results. The L-shape floating breakwater is found effective in reducing wave transmissions without the presence of the floating tanks, while the barge frame is the most effective in the motion reduction of the floating tanks. In addition, significant fluid resonant motions are identified for all investigated floating breakwaters, including the conventional one. Orienting the structure obliquely can improve the performance of the floating breakwaters of special configurations, especially the barge frame. The results and findings show the importance of considering the protected floating structures in the analysis when designing floating breakwaters for many types of marine structures, including floating fish farms and floating cities in coastal waters.

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An experimental study of double-row floating breakwaters

Cited by 19 publications

References 20 publications

Hydrodynamic Performance Improvement of Double-Row Floating Breakwaters by Changing the Cross-Sectional Geometry

Hydrodynamic Performance Improvement of Double-Row Floating Breakwaters by Changing the Cross-Sectional Geometry

Numerical Study on the Hydrodynamic Characteristics of a Double-Row Floating Breakwater Composed of a Pontoon and an Airbag

Effectiveness of Floating Breakwater in Special Configurations for Protecting Nearshore Infrastructures

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