—Porous breakwaters offer an alternative to conventional solid breakwater to create a tranquil water basin for the berthing of vessels by dissipate the energy of incoming waves. The efficiency of the porous breakwaters is governed by their porosity and their depth of submergence. In this study, experimental investigation has been carried out in a two-dimensional wave flume to investigate the effect of porosity on submerged and emerged porous breakwaters under various wave conditions. At 50 cm still water depth, interactions between regular waves (wave period, T
= 1.5 sec, 1.6 sec, 1.8 sec and 2.0 sec) and the fixed vertical porous breakwater of three different porosity ( n
= 0.45, 0.51 and 0.7) having three different structure heights (hb
= 40 cm, 50 cm and 60 cm) have been studied experimentally. Experimental results reveal that, minimum transmissi
on co-efficient (Kt
= 0.261) is obtained for breakwater with lowest porosity (n
= 0.45) and with emerged condition (when hb/h
= 1.2) for short wave, i.e. when T
= 1.5 sec. Minimum reflection co-efficient (Kr
= 0.089) is obtained for breakwater with highest porosity (n
=0.7) and with minimum submerged (hb/h
=0.8) condition. It is noticed that porosity has effect on the wave energy loss co-efficient also.
—Porosity, relative submergence, relative width, submerged and emerged breakwater.
Md. Ataur Rahman is with the Department of Water Resources Engineering, Bangladesh University of Engineering and Technology (BUET), Dhaka, Bangladesh (e-mail: firstname.lastname@example.org).
Aysha Akter is with the Department of Civil Engineering, University of Information Technology and Sciences (UITS), Dhaka, Bangladesh (e-mail: email@example.com).
Cite:Md. Ataur Rahman and Aysha Akter, "The Effect of Porosity of Submerged and Emerged Breakwater on Wave Transmission," International Journal of Environmental Science and Development vol. 5, no. 5, pp. 473-478, 2014.