Low-crested and submerged breakwaters in presence of broken waves

Functional design of low crested breakwaters requires an accurate prediction of wave transmission and set up in the protected areas. Nevertheless, commonly used formulae do not appear to be reliable enough, especially for structures located in shallow waters. The paper describes results from large-scale model tests conducted on rubble mound breakwaters exposed to breaking waves. Tests were carried out at the “Grosser WellenKanal” of Hannover, Germany. The model dimension, near to prototype, allowed minimizing scale effects connected to wave breaking. Existing formulas on wave transmission have been verified and influence of crest width and breaker index have been highlighted. Moreover the wave set-up behind the structure has been analysed showing the importance of momentum release of breaking waves for submerged breakwaters and of the mass balance for low crested ones. 8.