A phase-resolving wave model, combined with a two-dimensional depth-averaged current model, is developed to simulate a series of regular or random waves passing an L-shaped breakwater at an oblique angle. The near-shore wave processes, such as wave shoaling, reflection, refraction, deflection and wave breaking, and the wave-induced currents, such as flow circulation around the L-shaped breakwater, are all well reproduced. The model results of the mean wave heights and currents along 4 longshore and 6 cross-shore profiles generally agree well with the measured data, indicating the accuracy and robustness of the present model in simulating waves and currents around complex structures such as the L-shaped breakwater in this study.
L-shaped breakwaters have been widely used in coastal zones to reduce the wave attack, improve the ship mooring conditions and protect the shorelines from erosion. A pioneer study by Sayer et al (1995) experimentally investigated the wave and current fields around an L-shaped breakwater, using the state-of-the-art Coastal Research Facility at HR Wallingford, UK. In their experiments, an L-shaped breakwater was built on a sloping beach, and measurements of mean wave heights and depth-averaged currents at a number of locations were taken under both regular and random wave conditions. A significant circulation flow in the lee side of the breakwater was found in the case of regular incident waves, whilst a smaller scale flow circulation was found in the case of oblique random incident waves. Pan et al. (1999) used a phase-averaged wave and current model (WC2D) to simulate the hydrodynamics of the L-shaped breakwater under the same conditions of the said experiments. A generally good agreement between numerical results and experimental data was achieved, but due to the nature of the WC2D model, the phase-dependent values such as time varying surface elevation could not be taken into account.
