淤泥质海岸泥沙运动模拟及进港航道大风天回淤特性研究

建立波浪、潮流共同作用下的泥沙运动数学模型,提出了一种对泥沙运动模型率定与验证的新思路,即采用代表潮和代表波浪场对长期水动力进行模拟,并利用具有统计意义的代表含沙量场对泥沙起动各参数进行率定,最后采用不同风浪条件下的含沙量实测数据对模型进行验证.以连云港地区为例,对这种新思路进行了检验.研究结果表明,这种率定/验证思路可有效应用于粘性泥沙运动和航道回淤的模拟中.在所建思路与模型基础上,对淤泥质海岸大风作用下的泥沙运动特征及进港航道回淤特性进行了研究.结论显示大风作用下的含沙量分布形式与正常天气相似,但含沙量数值大幅增高.一次大风对航道回淤的影响时间应为大风期间与风后一段时间的总和,其中航道回淤最强的时刻发生在风后一天左右,然后随时间推移而逐渐降低至正常天气状态.最后,根据模型预测,连云港地区进港航道不会发生一次大风骤淤碍航的情况.

Numerical Modeling of Sediment Transport on Muddy Coast and Siltation Feature in Approach Channel under the Impact of Strong Wind

Combining the effects of both tides and waves, a 2-D numerical model was set up to simulate sediment transport on a muddy coast.A new concept of model validation, including calibration and verification, was proposed, in which representative tide and waves were used to model the long-term hydrodynamic conditions, calibration was performed by using yearly-representative suspended sediment concentration (SSC) values, and verification by using data observed under different wind-wave conditions. A case study, Lianyungang Harbor, China, was applied to test the proposed model validation concept. The results showed that the proposed methodology could be effectively applied in calibration and verification processes when modeling the cohesive sediment transport. Based on the model, the characteristics of SSC distribution around Lianyungang Harbor and siltation feature in approach channel under the impact of strong wind was discussed. The result showed the SSC field under the impact of a strong wind was similar to normal climates, only with the SSC values higher. The actual influence time of the strong wind not only contained the wind period, but also included several days after the wind, of which the greatest silting occurs at 1.0 day later after the wind, and then decreased until stable at the normal climate circumstance. At last it also showed an individual strong wind would not bring a hazard siltation in the approach channel.