Abstract
Floating breakwaters with a mooring system have been widely applied to protect marine infrastructures (e.g., artificial beach or island, aquaculture farm or marine vessels in harbors) from being destroyed by severe waves. In this paper, an innovative cylindrical dual pontoon-net floating breakwater was developed to enhance the wave attenuation capacity. This dual-module floating breakwater system was constructed as the prototype for on-site testing. A fully nonlinear time-domain model based on the coupled iterative solutions of the fluid integral equation and the pontoon-net dynamic equations was proposed to simulate the interactions between waves and the floating breakwater system. The flow field around the nets was simulated by introducing a porous-media model with Darcy’s law, while the deformation of the flexible nets was solved by using the lumped mass model. The instantaneous free surface was captured using the mixed Eulerian-Lagrangian (MEL) approach which employs an improved moving-grid technique based on the spring analysis to re-mesh the instantaneous water surface and the body wetted surface. On-site tests were also conducted to evaluate wave transmission performance of the floating breakwater system and to validate the numerical model. The comparisons show that the numerical solutions are in good agreement with the measured data. The effects of incident wave direction, wave period, wave height, net height, net number and net porosity on the hydrodynamic performance of the floating breakwater system were emphatically examined.
Similar content being viewed by others
References
Zang J., Gibson R., Taylor P. H. et al. Second order wave diffraction around a fixed ship-shaped body in unidirectional steep waves [J]. Journal of Offshore Mechanics and Arctic Engineering, 2006, 128(2): 89–99.
Koo W. C., Kim M. H. Freely floating-body simulation by a 2-D fully nonlinear numerical wave tank [J]. Ocean Engineering, 2004, 31(16): 2011–2046.
Koo W. C., Kim M. H. Fully nonlinear wave-body interactions with surface-piercing bodies [J]. Ocean Engineering, 2007, 34(7): 1000–1012.
Tang H. J., Huang C. C., Chen W. M. Dynamics of dual pontoon floating structure for cage aquaculture in a two-dimensional numerical wave tank [J]. Journal of Fluids and Structures, 2011, 27(7): 918–936.
Ning D. Z., Shi J., Zou Q. P. et al. Investigation of hydrodynamic performance of an OWC (oscillating water column) wave energy device using a fully nonlinear HOBEM (higher-order boundary element method) [J]. Energy, 2015, 83: 177–188.
Cheng Y., Ji C., Ma Z. et al. Numerical and experimental investigation of nonlinear focused waves-current interaction with a submerged plate [J]. Ocean Engineering, 2017, 135: 11–27.
Pham X. P., Varyani K. S. Evaluation of green water loads on high-speed containership using CFD [J]. Ocean Engineering, 2005, 32(5–6): 571–585.
Westphalen J., Greaves D. M., Williams C. J. K. et al. Focused waves and wave-structure interaction in a numerical wave tank [J]. Ocean Engineering, 2012, 45(4): 9–21.
Mittal S., Kumar V. Flow-induced oscillations of two cylinders in tandem and staggered arrangements [J]. Journal of Fluids and Structures, 2001, 15(5): 717–736.
Hadzic I., Hennig J., Peric M. et al. Computation of flow-induced motion of floating bodies [J]. Applied Mathematical Modelling, 2005, 29(12): 1196–1210.
Simonsen C. D., Otzen, J. F., Joncquez S. et al. EFD and CFD for KCS heaving and pitching in regular head waves [J]. Journal of Marine Science and Technology, 2013, 18(4): 435–459.
Sadat-Hosseini H., Wu P. C., Carrica P. M. et al. CFD verification and validation of added resistance and motions of KVLCC2 with fixed and free surge in short and long head waves [J]. Ocean Engineering, 2013, 59: 240–273.
Chen W. C., Dolguntseva I., Savin A. et al. Numerical modelling of a point-absorbing wave energy converter in irregular and extreme waves [J]. Applied Ocean Research, 2017, 63: 90–105.
Fredriksson D. W. Open ocean fish cage and mooring system dynamics [D]. Doctoral Thesis, Durham, NH, USA: University of New Hampshire, 2001.
Johansson D., Juell J. E., Oppedal F. et al. The influence of the pycnocline and cage resistance on current flow, oxygen flux and swimming behaviour of Atlantic salmon (Salmo salar L) in production cages [J]. Aquaculture, 2007, 265(1): 271–287.
Zhao Y. P., Bi C., Dong G. H. et al. Numerical simulation of the flow around fishing plane nets using the porous media model [J]. Ocean Engineering, 2013, 62: 25–37.
Bi C. W., Zhao Y. P., Dong G. H. et al. Numerical simulation of the interaction between flow and flexible nets [J]. Journal of Fluids and Structures, 2014, 45: 180–201.
Tang H. J., Huang C. C., Chen W. M. Dynamics of dual pontoon floating structure for cage aquaculture in a two-dimensional numerical wave tank [J]. Journal of Fluids and Structures, 2011, 27(7): 918–936.
Ning D. Z., Teng B., Eatock Taylor R. et al. Numerical simulation of non-linear regular and focused waves in an infinite water-depth [J]. Ocean Engineering, 2008, 35(8–9): 887–899.
Wei G., Kirby G. T., Sinha A. Generation of waves in Boussinesq models using a source function method [J]. Coast Engineering, 1999, 36(4): 271–299.
Hafsia Z., Haj M. B., Lamloumi H. et al. Comparison between moving paddle and mass source method for solitary wave generation and propagation over a steep sloping beach [J]. Engineering Applications Computional Fluid Mechanics, 2009, 3(3): 355–368.
Fenton J. D. A fifth order stokes theory for steady waves [J]. Journal of Waterway, Port, Coastal and Ocean Engineering, 1985, 111(2): 216–234.
Ji C., Cheng Y., Yang K. et al. Numerical and experimental investigation of hydrodynamic performance of a cylindrical dual pontoon-net floating breakwater [J]. Coast Engineering, 2017, 129: 1–16.
Goda Y., Suzuki Y. Estimation of incident and reflected waves in random wave experiments [C]. Proceedings of the 15th Coastal Engineering Conference, Honolulu, Hawaii, USA, 1976, 828–845.
Cheng Y., Ji C. Y., Zhai G. J. et al. Nonlinear analysis for ship-generated waves interaction with mooring line/riser systems [J]. Marine Structures, 2018, 59: 1–24.
Wu G. X., Eatock Taylor R. The coupled finite element and boundary element analysis of nonlinear interactions between waves and bodies [J]. Ocean Engineering, 2003, 30(3): 387–400.
Batina J. T., Unsteady Euler airfoil solutions using unstructured dynamic meshes [C]. Proceedings of the 27th AIAA aerospace sciences meeting, Reno, Nevada, USA, 1990, 1381–1388.
Wu Y. S., Ding J., Gu X. K. et al. The progress in the verification of key technologies for floating structures near islands and reefs [C]. Proceedings of the Thirtieth International Ocean and Polar Engineering Conference, Shanghai, China, 2020.
Acknowledgements
This work was supported by the State Key Laboratory of Ocean Engineering, Shanghai Jiao Tong University (Grant No. 1905), the Newton Advanced Fellowships (Grant No. NAF\R1\180304) by the Royal Society.
Author information
Authors and Affiliations
Corresponding author
Additional information
Projects supported by the National Natural Science Foundation of China (Grant Nos. 52025112, 51861130358 and 52111530137).
Biography
Yong Cheng (1986-), Male, Ph. D., Associate Professor, E-mail: chengyong@just.edu.cn
Rights and permissions
About this article
Cite this article
Cheng, Y., Ji, Cy., Gu, Xk. et al. Hydrodynamics of a dual-module pontoon-net floating breakwater system: Numerical simulations and prototype tests. J Hydrodyn 33, 915–927 (2021). https://doi.org/10.1007/s42241-021-0081-1
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s42241-021-0081-1