Hydrodynamic characteristics of a submerged trapezoidal artificial reef unit

Submerged structures serve as wave attenuators and are widely adopted for protecting the coast against erosion or to reduce forces on structures situated on its leeward side. Conventional submerged breakwaters are composed of rubble stones, and the sources for quarrying such stones have depleted drastically over a period of time. The artificial reefs are a replacement for submerged breakwaters formed by natural rocks due to its minimum impact on the marine environment, flexibility in molding to any desired shape and size. It is also believed to serve as a habitable environment to marine flora and fauna. In this study, a comprehensive experimental investigation is carried out in order to examine the effect of perforations on a submerged artificial reef exposed to regular and random waves. The tests with models of crest width (B) of 0.2 m and crest height (h) of 0.4 m are conducted for three different degrees of submergence (d/h) of 1.5, 1.38 and 1.25 in three different water depths, d. The article emphasizes the influence of relative water depth, relative crest width and the nature of the surface of the structure (impermeable or permeable) on its hydrodynamic performance characteristics.