The Effects of Porosity of Submerged Breakwater Structures on Non-Breaking Wave Transformations

Faridah Jaffar Sidek, and Muhammad Al-Jeffry Abdul Wahab, (2007) The Effects of Porosity of Submerged Breakwater Structures on Non-Breaking Wave Transformations. Malaysian Journal of Civil Engineering, 19 (1). pp. 17-25.

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Affiliations

Universiti Teknologi Malaysia, Coastal & Offshore Engineering Institute.
Universiti Teknologi Malaysia. Faculty of Civil Engineering.

Abstract

Development of an innovative porous submerged breakwater structure which could be used for the purpose of coastal restoration is underway in the Coastal & Offshore Engineering Institute’s research laboratory. Prior to developing the structure, laboratory investigations on models (typifying porous submerged breakwater structures) that could provide experimental information of the influence of porosity on non-breaking wave transformations have been undertaken. A series of tests to study the effect of porosity of submerged breakwater model structures on the process of non-breaking wave transformations have been carried out. A hollow framework-shaped test model was used. Three models each with three different porosities ranging from 0.40 to 0.80 were constructed. From laboratory tests, results obtained have been analysed to check the performance of the models to attenuate waves. Test results have indicated that the transmission coefficient, KT increased with increasing model porosity. The wave reflection coefficient, KR of the model tested ranged from 0.01 to 0.31. Energy loss of the primary waves was found to be highest when the parameter kd was equal to 1.9 and lowest when the porosity of the model was found to be large.

Kerja-kerja untuk membangunkan satu pemecah ombak tenggelam yang berliang untuk kegunaan pemulihan pantai secara inovatif sedang dilaksanakan di makmal penyelidikan Institut Kejuruteraan Pantai dan Lepas Pantai. Sebelum merekabentuk struktur itu, kajian makmal ke atas model kajian yang mencontohi struktur pemecah ombak poros ditenggelami yang dapat mengesahkan pengaruh keliangan terhadap kelemahan tenaga ombak telah dikaji. Satu siri ujian yang merangkumi kajian untuk memperoleh maklumat tentang pengaruh keliangan pada struktur tersebut terhadap proses penghantaran ombak yang tidak pecah telah dijalankan. Model kajian yang merupakan rangka yang berongga telah digunakan. Tiga model pemecah ombak berliang yang bergeomatrikan tiga nilai keliangan yang berbeza dari 0.40 to 0.80 telah dibina. Daripada kajian makmal, hasil yang diperolehi telah dianalisis untuk memantau prestasi model kajian dalam melemahkan tenaga ombak. Hasil kajian menunjukkan bahawa koefisien penghantaran, KTt, bertambah dengan peningkatan nilai keliangan. Koefisien pantulan ombak, KR didapati berada di dalam julat 0.01 hingga 0.31. Kehilangan tenaga ombak adalah tinggi bila parameter kd adalah bersamaan dengan 1.9 dan rendah bila keliangan adalah besar.

Item Type:

Journal

Additional Information:

The authors are indebted to the Coastal & Offshore Engineering Institute of Universiti Teknologi Malaysia for providing financial funding, technical staff and laboratory facilities to ensure the successful completion of the above project

Keywords:

Permeable breakwater; Porosity; Submerged breakwater; Wave attenuation; Wave Transmission Pemecah ombak boleh telap; keliangan; pemecah ombak tenggelam; pelemahan tenaga ombak; transmisi ombak

Subjects:

T Technology, Engineering

ID Code:

6459