福建海坛湾波流双向耦合下水动力特征

Study of Hydrodynamics Using a BiDirectional WaveCurrent Coupled Model in Haitan Bay, Fujian Province

摘要:

采用MIKE 21软件中SW(spectral wave)波浪模块和FM(flow model)潮流模块，将潮流模块计算得到的水位与流速输入波浪模型，将波浪模块计算得到的辐射应力输入潮流模型，建立海坛湾波流双向耦合的水动力数学模型.分别计算纯潮流和纯波浪作用下的潮流场和波浪场，计算结果与实测数据吻合良好，再分别对波流双向耦合作用下的潮流场和波浪场进行了模拟.比较结果表明：波流耦合作用对流速和波高都有一定的影响；在波流异向特性明显的区域，波高增大显著；涨落急时刻波高在近岸区域的衰减速率和纯波浪作用下的较一致；落急时刻波高开始显著衰减的位置明显早于涨急时刻；波浪辐射应力在破碎带附近对流速的影响最大.

Abstract:

In this paper, a 2D bidirectional wavecurrent coupled model in Haitan Bay was set up based on the MIKE 21 SW wave module and FM current module. The effects of wave and current interactions were incorporated by extracting the radiation stresses from wave simulations into FM model, and extracting the water levels and velocities from flow simulations into SW model, respectively. The flow fields and wave fields in Haitan Bay under pure current and pure wave condition were simulated respectively, and calibrated by the field measured tidal flow and wave data. Then, the well validated models were employed to model the flow fields and wave fields under wavecurrent interaction. The results show that the wavecurrent interaction has a great influence on both flow velocity and wave height and the wave height significantly increases if the wave and current are in the opposite direction; the decay rate of wave height in the inshore area in both flood current and ebb current is in accordance with that in pure wave condition; the position for the wave height that begins to decrease in ebb current is obviously earlier than that in flood current; the radiation stress has a significant influence on the flow velocity in the wave breaking zone.