Wave loading distribution of oscillating water column caisson breakwaters under non-breaking wave forces

Wave energy is one of the most potential marine energy resources in Taiwan, especially in the northeast and east coast of Taiwan. There are numerous existing wave energy devices. Among them, Oscillating Water Column (OWC) caisson breakwater is very suitable for the harbors in Taiwan. This multiple function structure can generate electric power and protect harbor. To evaluate the stability of OWC caisson breakwater, the loadings induced by wave acted on the OWC caisson breakwater are analyzed. Experiments of a small scale physical model of OWC caisson breakwater is presented in this study. The model is fixed in the wave flume and the wave pressures acting on the structure are recorded. It is found that wave pressure at oscillating water column caisson breakwaters is smaller than the wave pressure at vertical wall. The wave loadings calculated with the suggestion of Sainflou (1928) and Goda (1985) are compared with the test results. The applicability of the empirical formulas is also discussed. Under the selected wave condition, the Sainflou's formula overestimates the wave pressure acting on the OWC caisson breakwater. Goda's formula (1973) provides good estimation for the force estimation but tends to underestimate the momentum and could possibly result in structure overturning.