Investigation and Prediction of the Evolution of Medium-Long-Period Waves Across a Coral Reef

The evolution of medium-long-period waves on coral reefs is crucial for the safety of coastal structures and sediment transport. This study investigated the evolution of these waves across a coral reef through smoothed particle hydrodynamics to elucidate the transfer of wave energy and develop a prediction method for reef flat waves. A numerical wave flume with a relaxing wave-making zone was also established and verified. For medium-long-period waves, the reflection coefficient gradually decreases as the wave period increases. Waves were identified as long or short, depending on the incident wave frequency. At the reef edge, wave energy moves toward high frequencies, resulting in an increase in short waves’ height. On the reef flat, the heights of long and short waves are equal. As the wave period increases and the reef flat height decreases, the probability density distribution of waves on the reef flat becomes skewed, the peak and fat tail characteristics become pronounced, and the forward-pitching waveform becomes evident. A data mapping method based on extreme gradient boosting (XGBoost) was proposed to predict the occurrence of reef flat waves using far-ocean wave data. The results indicate that the sooty tern optimization algorithm (STOA)-XGBoost model exhibits the best performance.