Transmission of solitary waves through slotted barriers: A laboratory study with analysis by a long wave approximation

Economic and long-term social impacts of tsunami waves, as shown in the 2004 Indian Ocean tsunami, have been devastating. In addition to the passive measures such as the tsunami early warning systems, active protective measures such as tsunami breakwaters and tsunami-resistant buildings are also necessary. Slotted barriers are low cost structures that can be very effective in reducing the transmitted energy of long waves. In this study, the transmission of tsunami waves, with the leading wave being modeled by a solitary wave, through slotted barriers in the form of a row of circular cylinders is studied experimentally. The results are also analyzed by a method based on long wave approximations. It is found that the spacing between two adjacent cylinders is one of the main factors that control the transmission of solitary waves through slotted barriers. Reflection coefficients and the reduction of drag force on coastal structures protected by slotted barriers are also discussed in the paper.