Wave-induced set-up over barrier reefs under the effect of tidal current

Abstract

In this study, a series of new laboratory experiments were performed in a wave-current flume in the presence/absence of tidal current. Experimental results are reported for a variety of combined wave-current conditions based on an idealized barrier reef model. Result analysis shows that the mean water level on the reef flat was consistently lower during the shoreward current (flood tide) than that during the seaward current (ebb tide). Maximum wave set-up on the reef flat decreased significantly as the current flowrate changed from its seaward maximum to its shoreward maximum. A theoretical model, which was derived based on the cross-shore balances of momentum and energy, was proposed to reproduce the wave set-up on the reef flat in the presence of current. The model was then validated by the laboratory data. The key model parameter was found to decrease rapidly with increasing current flowrate.

Keywords:

• Barrier reef
• tidal current
• wave breaking
• wave set-up
• wave-current flume

Acknowledgements

The first author thanks Mr Wancheng Yuan and Mr Zhengjiang Tang at Changsha University of Science and Technology, China, for their assistance in the laboratory work.

Additional information

Funding

This study is supported financially by the National Natural Science Foundation of China [grant number 51679014], [grant number 51839002], [grant number 51309035] and by the Hunan Science and Technology Plan Program [grant number 2017RS3035].