Numerical study of nearshore hydrodynamics and morphology changes behind offshore breakwaters under actions of waves using a sediment transport model coupled with the SWASH model

ABSTRACT

This paper presents the results of numerical study on the wave-induced currents and morphology changes due to the complicated interaction between waves and a sandy beach with shore-parallel breakwaters set on. The study was based on the SWASH wave model coupled with a sediment transport model developed in this research. The simulated results of the coupling model were compared with the published laboratory experimental data. The good agreements were obtained for both wave-induced currents and formation of salient and tombolo behind breakwaters. The models were also applied for studying the evolution of wave-induced currents associated with topography changes of a sandy beach. The wave-induced currents and sediment transport processes have a strong relationship and their interaction could reach a quasi-equilibrium state in which the changes of current pattern and bathymetry become very slow. Numerical results of shoreline response mode were also compared with a published empirical formula and confirmed good agreements.

KEYWORDS:

• Sediment transport model
• SWASH
• wave-induced currents
• beach erosion

Acknowledgments

This work has been done under the financial support of Vietnam’s National Foundation for Science and Technology Development (NAFOSTED) by the project grant number 105.06-2016.01. The financial support from NAFOSTED is gratefully acknowledged. The first author wishes to give thanks to Vietnam Institute of Sea and Island (VISI) for providing with good condition for the research. The first author wishes to send special thanks to Prof. Yee-Meng Chiew from School of Civil and Environmental Engineering, Nanyang Technological University, Singapore for kindly providing his paper.

Additional information

Funding

This work was supported by the NAFOSTED [105.06-2016.01].