水东湾地貌形态演变数值模拟

Numerical simulation of the evolution of the morphological features of Shuidong Bay

为了研究泻湖型海湾内经常出现的湾中岛的形成机理,应用水平二维潮流、泥沙输移和地形演变耦合模型,对具有典型的沙坝泻湖地貌形态的水东湾的湾中岛的形成和演化进行了数值模拟,成功地模拟出了涨潮三角洲(大洲岛)的形成过程,计算结果与实际地貌形态总体符合。模型中分别考虑了全沙输沙和推移质输沙两种输沙情况。结果表明,水东湾湾中岛是由涨潮流引起的泻湖内泥沙不断淤积而形成的,是一种涨潮三角洲的地貌形态;全沙输沙模式比推移质输沙模式更适合这一地形演化过程的模拟。模拟结果也再现了湾中岛在25a期间的地形变化过程,这一研究结果为通过计算数值模拟来研究一般海湾的地貌形态的形成机理和演化过程提供了实际算例。

To analyze the formation mechanism of an island in a lagoon-type bay, the coupling model of horizontal 2-D tidal current, sediment transport, and terrain evolution is adopted to reproduce the morphological features of Shuidong Bay and the focus is on the formation and evolution of Dazhou Island in Shuidong Bay. The calculation results are consistent with the actual topography. Two models of sediment transport, i.e., total load and bed load sand transport models, are considered. The simulation shows that Dazhou Island in Shuidong Bay is formed by the continuous deposition of silts in the lagoon under the influence of rising tide and is a geomorphic form of flood tide delta. The total load sediment transport model is more suitable for simulating the terrain evolution process than the bed load sediment transport model. This study explores the formation mechanism and evolution process of the general bay morphology through numerical simulation.