...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Ocean Dynamics >Modeling equilibrium bed profiles of short tidal embayments: On the effect of the vertical distribution of suspended sediment and the influence of the boundary conditions
【24h】

Modeling equilibrium bed profiles of short tidal embayments: On the effect of the vertical distribution of suspended sediment and the influence of the boundary conditions

机译：短潮汐潮汐的平衡河床剖面建模：关于悬浮沉积物垂直分布的影响和边界条件的影响

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

In many tidal embayments, bottom patterns, such as the channel-shoal systems of the Wadden Sea, are observed. To gain understanding of the mechanisms that result in these bottom patterns, an idealized model is developed and analyzed for short tidal embayments. In this model, the water motion is described by the depth- and width-averaged shallow water equations and forced by a prescribed sea surface elevation at the entrance of the embayment. The bed evolves due to the divergence and convergence of suspended sediment fluxes. To model this suspended-load sediment transport, the three-dimensional advection-diffusion equation is integrated over depth and averaged over the width. One of the sediment fluxes in the resulting one-dimensional advection-diffusion equation is proportional to the gradient of the local water depth. In most models, this topographically induced flux is not present. Using standard continuation techniques, morphodynamic equilibria are obtained for different parameter values and forcing conditions. The bathymetry of the resulting equilibrium bed profiles and their dependency on parameters, such as the phase difference between the externally prescribed M_2 and M_4 tide and the sediment fall velocity, are explained physically.rnWith this model, it is then shown that for embayments that are dominated by a net import of sediment, morphodynamic equilibria only exist up to a maximum embayment length. Furthermore, the sensitivity of the model to different morphological boundary conditions at the entrance of the embayment is investigated and it is demonstrated how this strongly influences the shape and number of possible equilibrium bottom profiles. This paper ends with a comparison between the developed model and field data for the Wadden Sea's Ameland and Frisian inlets. When the model is forced with the observed M_2 and M_4 tidal constituents, morphodynamic equilibria can be found with embayment lengths similar to those observed in these inlets. However, this is only possible when the topographically induced suspended sediment flux is included. Without this flux, the maximum embayment length for which morphodynamic equilibria can be found is approximately a third of the observed length. The sensitivity of the model to the topographically induced sediment flux is discussed in detail.
机译：在许多潮汐港湾中，都可以看到海底模式，例如瓦登海的航道-浅滩系统。为了了解导致这些底部模式的机制，开发并分析了一个理想的模型，用于潮汐的短暂停留。在该模型中，水运动由深度和宽度平均的浅水方程式描述，并由在浮标入口处的指定海平面高程强迫。由于悬浮的泥沙通量的发散和收敛，该床层得以演化。为了模拟这种悬浮负荷的泥沙运移，在深度上对三维对流扩散方程进行积分，并在宽度上进行平均。一维对流扩散方程中的沉积物通量之一与局部水深的梯度成比例。在大多数模型中，这种地形诱导的通量不存在。使用标准的连续技术，可以针对不同的参数值和强制条件获得形态动力学平衡。物理上解释了所得平衡床剖面的测深图及其对参数的依赖性，例如外部规定的M_2和M_4潮汐之间的相位差和沉积物沉降速度。以沉积物的净进口为主导，形态动力学平衡仅在最大嵌入长度之前存在。此外，研究了模型对入口入口处不同形态边界条件的敏感性，并证明了其如何强烈影响可能的平衡底部轮廓的形状和数量。本文最后对瓦登海的阿默兰岛和弗里斯兰入海口的开发模型与现场数据进行了比较。当用观察到的M_2和M_4潮汐成分强迫模型时，可以发现形态动力学平衡，其沉降长度与在这些入口中观察到的相似。但是，这只有在包括地形诱发的悬浮泥沙通量的情况下才有可能。如果没有该通量，则可以找到形态动力学平衡的最大嵌入长度约为观察到的长度的三分之一。详细讨论了该模型对地形诱发的泥沙通量的敏感性。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号