Version 1
: Received: 27 October 2022 / Approved: 27 October 2022 / Online: 27 October 2022 (11:03:12 CEST)
Version 2
: Received: 8 November 2022 / Approved: 8 November 2022 / Online: 8 November 2022 (06:44:38 CET)
Nguyen, N.-M.; Van, D.D.; Le Duy, T.; Pham, N.T.; Duc Dang, T.; Tanim, A.H.; Wright, D.; Thanh, P.N.; Anh, D.T. The Influence of Crest Width and Working States on Wave Transmission of Pile–Rock Breakwaters in the Coastal Mekong Delta. J. Mar. Sci. Eng.2022, 10, 1762.
Nguyen, N.-M.; Van, D.D.; Le Duy, T.; Pham, N.T.; Duc Dang, T.; Tanim, A.H.; Wright, D.; Thanh, P.N.; Anh, D.T. The Influence of Crest Width and Working States on Wave Transmission of Pile–Rock Breakwaters in the Coastal Mekong Delta. J. Mar. Sci. Eng. 2022, 10, 1762.
Nguyen, N.-M.; Van, D.D.; Le Duy, T.; Pham, N.T.; Duc Dang, T.; Tanim, A.H.; Wright, D.; Thanh, P.N.; Anh, D.T. The Influence of Crest Width and Working States on Wave Transmission of Pile–Rock Breakwaters in the Coastal Mekong Delta. J. Mar. Sci. Eng.2022, 10, 1762.
Nguyen, N.-M.; Van, D.D.; Le Duy, T.; Pham, N.T.; Duc Dang, T.; Tanim, A.H.; Wright, D.; Thanh, P.N.; Anh, D.T. The Influence of Crest Width and Working States on Wave Transmission of Pile–Rock Breakwaters in the Coastal Mekong Delta. J. Mar. Sci. Eng. 2022, 10, 1762.
Abstract
The coastline in the Ca Mau and the Kien Giang provinces of the Vietnamese Mekong Delta has been severely eroded in recent decades. Pile-Rock Breakwaters (PRBW) are one of the most widely adopted structures for controlling shoreline erosion in this region. These structures are effective for wave energy dissipation, stimulating sediment accumulation, and facilitating the restoration of mangrove forests. These breakwaters are generally considered to be best-engineering practice however there is currently insufficient scientific evidence with regard to specific structural design aspects. This can lead to PRBW structures being compromised when deployed in the field. This study uses a physical model of a PRBW in a laboratory to investigate several design parameters, including crest width and working states (i.e. submerged, transition, and emerged), and investigates their relationship with the wave transmission coefficient, wave reflection coefficient, and wave energy dissipation. To investigate these relationships further, empirical formulas were derived for PRBWs under different sea states and crest widths to aid the design process. The results showed that PRBW width had a significant influence on the wave energy coefficients. The findings revealed that the crest width of the breakwater is inversely proportional to the wave transmission coefficient (Kt) under the emerged state. The crest width is also proportional to the wave reduction efficiency and wave energy dissipation in both working states (i.e., submerged and emerged states). The front wave disturbance coefficient (Kf) was found to be proportional to the wave reflection coefficient, and the wave height in front of the structure was found to increase by up to 1.4 times in the emerged state. The wave reflection coefficient requires special consideration to reduce the toe erosion in the structure. Lastly, empirical equations including linear and non-linear formulas were compared with previous studies for different classes of breakwaters. These empirical equations will be useful for understanding the wave transmission efficiency of PRBWs. The findings of this study provide important guidance for PRBW design in the coastal area of the Mekong Delta.
Keywords
pile-rock breakwater; wave transmission; wave reflection; energy dissipation; physical model; East Sea of Mekong Delta
Subject
Engineering, Marine Engineering
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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Commenter: Duong Anh
Commenter's Conflict of Interests: Author