波流共同作用下珊瑚岸礁的水动力学特性研究

There are sound ecological, environmental, geologic as well as engineering implications for nearshore coral reef hydrodynamics. This topic has drawn extensive research interests over decades in foreign counrtires but such research is still very limited in China. This research project will investigate the hydrodynamic characteristics of fringing coral reefs under combined effects of waves and tidal current experimentally and numerically. Laboratory experiments will be conducted in a wave-current flume, using an idealized fringing coral reef model with the allowrance of the horizontal circulation. The laboratory studies will focus on： (1) The breaking-wave properties of regular waves, including breaking location and height, breaker type as well as surfzone width; (2) The transformation of both regular and irregular waves, including wave incidence,reflection,transmission, attunation as well as generation of both higher harmonics and intra-gravity waves; (3) The cross-reef wave-induced setup and wave-driven current under both regular and irregular waves; (4) The turbulence characteristics and the undertow in the surf zone under regular waves. The high-order Boussinesq model will be improved to simulate the interaction of waves with fringing reefs in the presence of currents, and the numerical results will be compared with the experimental measurements. The project results will enrich the current knowledge and theories of coral reef hydrodynamics, and they will also provide valuable reference for research on similar coastal profiles such as submerged breakwaters and bar beaches.

近岸珊瑚礁的水动力学问题具有重要的生态、环境、地质和工程学意义。 近几十年来，该课题在国外得到了较为广泛的研究，而国内相关研究则相对很少。 本项目拟通过物理模型实验和数值模拟的方法来研究波浪和潮汐流共同作用下珊瑚岸礁的水动力学特性。物理实验将在波流水槽中进行并采用了考虑水平环流存在的概化岸礁模型。实验研究包括：（1）规则波的破碎特征，包括破碎点的位置和波高、破碎类型以及破碎带的宽度；（2）规则波和不规则波的演变，包括波浪的入射、反射、透射、衰减以及高频波和低频波的产生；（3）规则波和不规则波破碎产生的增水和波生流；（4）规则波破碎带内的湍流特征和海底回流。数值模拟将运用改进的高阶Boussinesq模型来模拟波流和岸礁间的相互作用，并与实验结果进行对比验证。项目的研究成果将丰富和发展了珊瑚岸礁水动力学理论，对于研究潜堤，沙坝等其他类似海岸地形也具有相当的参考价值。

近岸珊瑚礁的水动力学问题具有重要的生态、环境、地质和工程学意义。 近几十年来该课题在国外得到了较为广泛的研究，而国内相关研究则相对很少。 本项目拟通过物理模型实验、数值模拟和理论模型的方法来研究波浪和潮汐流共同作用下珊瑚岸礁的水动力学特性。物理实验将在波流水槽中进行并采用了考虑水平环流存在的概化岸礁模型。实验研究包括：（1）规则波的破碎特征，包括破碎点的位置和波高、破碎类型以及破碎带的宽度；（2）规则波和不规则波的演变，包括波浪的入射、反射、透射、衰减以及高频波和低频波的产生；（3）规则波和不规则波破碎产生的增水和波生流；（4）规则波破碎带内的湍流特征和海底回流。数值模拟运用了改进的高阶Boussinesq模型来模拟礁面形态改变时波浪与岸礁的相互作用，并与现场观测进行对比验证。最后基于动量守恒建立了水平方向二维的理论模型，该模型能够合理地预测水平环流存在时礁坪上波浪增水的产生。项目的研究成果将丰富和发展了珊瑚岸礁水动力学理论，对于研究潜堤，沙坝等其他类似海岸地形也具有相当的参考价值。