Waves and currents can affect each other and their interaction is of prime importance in coastal waters. Huanghua Harbor is one of the major harbors for energy output in China, which suffers a strong wave-current interaction. A 2D hydrodynamic numerical model is set up by Delft3D. The well validated model is used to reproduce wave-current interaction on velocity and water level in Huanghua Harbor coastal water. The results indicate that normal waves play a minor role on current velocity and water level, however, the strong waves have a great influence on velocity and its horizontal distribution patterns. Significant velocity variations occur in the head of jetties and along the jetties where variation of velocity can reach 0.4 m/s, and the average water level notably increases by 3.63~7.93% with the maximum occurs at low tide level under the strong wave action.
Wave-current interactions, especially for solidary waves, have been widely identified to evaluate the effects induced by tsunamis or storm surge in coastal areas, which is of prime importance in coastal structure protection and hazards mitigation (Zhang, Zheng, Jeng and Guo, 2015). In the past decades, the mechanics of wave-current interaction have been widely studied by theoretical methods (Carrier, Wu and Yeh, 2003) and laboratory experiments (Umeyama, 2009; Umeyama, 2011). In addition to theoretical and experimental studies, numerical models based on the Navier-Stokes (NS) equations are developing rapidly for the prediction of wave-current interactions in recent years (Zhang and Yim, 2015; Zhang, Zheng, Jeng and Guo, 2015) and their applications have been proved to be feasible and successful. For coastal areas, the hydrodynamic environment is often influenced by the tidal current, wave, wind and their interactions that will affect the sediment dynamics and morphodyamics. Among these influence factors, wave-current interaction plays a key role in coastal water and nearshore regions where it is closely linked with human's activities. Waves can be affected by currents attribute to refraction, blocking and modification of bed shear stress that modify the wave frequency and phase speed. Conversely, the currents can be strongly forced and modified by waves according to the additional momentum and mass fluxes, especially in surf zone (Rong, Hetland, Zhang and Zhang, 2014). It has been widely found out in the coastal region that following tidal current decreases the wave height whereas opposing current increases the wave height. And currents are also modulated by wave as the following currents' upper speed decrease toward the wave trough and increase due to the wave crest (Jia, Wen, Pan, Liu and He, 2015).
