Impact of wave energy converters on infragravity waves: An experimental investigation

Infragravity waves play an important role in the nearshore water dynamics and significantly impact coastal processes and port operations. One potential way to reduce the influence of long waves is to take advantage of wave energy converters (WECs) and their ability to alter the downstream wavefield. A small-scale laboratory experiment is used to explore the effect of WECs on the infragravity wave generation over the steep reef platform. The long wave is generated using a bichromatic wave group, and the WECs are designed as oscillating water columns that resonate at the wave group harmonics, providing the greatest impact on the wavefield dynamics. The experiments are conducted in five stages progressively increasing the complexity of the tested set-up. The results demonstrate that the reef platform causes a significant amplification of the infragravity wave amplitude for the tested wave conditions. Placing the WECs upstream of the reef platform reduces the long wave amplitude over the reef flat, where maximum attenuation occurs with the largest number of WECs tested. •In laboratory experiments, long waves are generated using nonlinear wave interaction in the wave group.•Infragravity waves are significantly amplified on the reef platform.•Wave energy converters effectively attenuate infragravity waves by interacting with primary short waves in a wave group.•Oscillating water columns without any orifice effects have the strongest interaction with the incident wave.