THE EFFECTS OF POROSITY OF SUBMERGED BREAKWATER STRUCTURES ON NON-BREAKING WAVE TRANSFORMATIONS
DOI:
https://doi.org/10.11113/mjce.v19.15744Keywords:
Permeable breakwater, Porosity, Submerged breakwater, Wave attenuation, Wave TransmissionAbstract
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.References
Abdul Wahab, M.A. (2006) Laboratory Investigations on the Performance of Porous Submerged Breakwater, B. Civ. Eng. Thesis, Faculty of Civil Engineering, Universiti Teknologi
Malaysia.
Black, K and Mead, S. (1999) Submerged Structures for Coastal Protection, ASR, Marine and Freshwater Consultants, New Zealand.
Dean, R. D. and Dalrymple, R. A. (1991) Water Wave Mechanics for Engineers and Scientists, USA : World Scientific.
Ting, C. L., Lin, M. C., Cheng, C. Y. (2004) Porosity effect on non-breaking surface waves over permeable submerged breakwaters. Coastal Engineering, 50: 213-224.
Huang, C. J., Chang, H. H., Hwung, H. H. (2003) Structural permeability effects on the interaction of a solitary wave and a submerged breakwater. Coastal Engineering, 40: 1– 24.
Dattatri, J., Raman, H. and Shankar, J.N. (1978) Performance characteristics of submerged breakwaters. Proceedings of the 16th Inernational. Conference in Coastal Engineering,
ASCE, Hamburg, Germany, pp. 2153–2171.
Gu, Z., Wang, H. (1991) Gravity waves over porous bottoms. Coastal Engineering, 15; 497– 524
Pilarczyk K. W. (2003) Design of low-crested (submerged) structures. Proceedings of the 6th International Conference on Coastal and Port Engineering in Developing Countries, Colombo, Sri Lanka, pp 1-19
Losada, I.J., Losada, M.A. and Martin, F.L. (1995) Experimental study of wave induced flow in porous structure. Coastal Engineering, 26: 77-98.
Sollitt, C.K. and Cross, RH (1972) Wave transmission through permeable breakwaters. Proceedings of the 13th International Conference in Coastal Engineering, pp 1827-1846.
