Diffraction of Waves by Shore-Connected Breakwater

The diffraction diagrams commonly used by coastal engineers to determine the shelter afforded by a shore-connected breakwater are generally based upon Sommerfeld’s exact solution, with only limited experimental data to define the range of applicability. In order to establish this range more precisely, wave-height distributions in the shadow-zone of an impermeable shore-connected breakwater, 30-ft (9-m) in length, were measured in a large hydraulic-model basin and compared to Sommerfeld’s solution. The influence of a wave-splitter plate and energy dissipation on the structure were studied in experiments with the wave generator running continuously and also intermittently (stop-start). Detailed diffraction profiles were obtained both near the structure and at great distances, as far as 22 wavelengths from the breakwater. Long-crested regular waves were generated and found to be significantly non-uniform in height along the 65-ft (19.5-m) crest line under all conditions.