Hydraulic performance of single perforated seawalls

Seawalls are one of the most commonly used protection structures along the coastal areas.The main benefits to coastal protection occurs as preventing the site from erosion, floodingand corruptive wave action. Therefore vertical seawalls are highly preferred considering therequirements that of they need less space, material and construction time. However, due tovertical and permeable front surface, strong reflection of incoming waves are effective onstructure which may cause inevitable problems. Furthermore, reflection of waves causesnavigation problems for vessels and worsens mooring conditions, cargo/passenger movementsin the harbour basins. Besides there may be scour risk at structure toe and also erosionbecause of the wave reflections. In order to resolve these problems perforated structures havebeen preferred.In this study, in order to investigate the hydraulic performance of single perforated verticalwalls against reflection and transmission, a series of experiments have been performed. Thetests have been carried out under regular wave conditions and wave overtopping is neglected.Circular holes have been used to reflect the porosity of the structure. The perforated wallmodels have three different porosities in order of 20%, 26% and %40.Consequently, tests have revealed that the most effective parameters for the reflection andtransmission performance of the perforated vertical walls are the relative wave height and thestructure porosity. Comparing the three different models, 40% of porosity came out with thehigher reflection and lower transmission ratios. It?s realized that due to the increasing waveheights wave reflection also inceases. The wave period has no relation with the wavereflection and transmission.Key words: Single perforated vertical walls, hydraulic performance, wave reflection, wavetransmission