Fluvio-deltaic sedimentation: A generalized Stefan problem
Fluvio-deltaic sedimentation: A generalized Stefan problem
复制标题
DOI：
10.1017/s0956792500004198
复制
发表时间：
2000-10
影响因子：
1.9
通讯作者：
J. Swenson;V. Voller;C. Paola;G. Parker;J. Marr
中科院分区：
文献类型：
--
作者：
J. Swenson;V. Voller;C. Paola;G. Parker;J. Marr
提出了一个稳定供沙、基准面不稳定的沉降型河流-三角洲盆地的沉积模型。我们证明了河流三角洲盆地中的质量传递类似于广义Stefan问题中的热传递，其中盆地的海岸线代表相前沿。通过对相变文献中变形网格技术的推广，我们得到了该系统中泥沙运动和沉积控制方程的数值解。通过对热平衡积分法的改进，得到了与数值解吻合较好的半解析解。我们为盆地构造了一个无量纲群的空间，并对这个空间进行了系统的探索，以说明每个群对海岸线轨迹的影响。我们的模型结果表明，所有下沉的河流三角洲盆地都表现出标准的自退岸线轨迹，在此轨迹中，短暂的岸线推进之后是较长的岸线后退。基准线自行车产生的海岸线响应相对于自动撤退信号有所不同。与以前的研究相反，我们既没有观察到海岸线和基准面之间的强烈相移，也没有观察到随着基准面循环频率的减少，海岸线响应的幅度显著衰减。然而，海岸线对基准面旋回的响应幅度是盆地年龄的函数。
We present a model of sedimentation in a subsiding fluvio-deltaic basin with steady sediment supply and unsteady base level. We demonstrate that mass transfer in a fluvio-deltaic basin is analogous to heat transfer in a generalized Stefan problem, where the basin's shoreline represents the phase front. We obtain a numerical solution to the governing equations for sediment transport and deposition in this system via an extension of a deforming-grid technique from the phase-change literature. Through modification of the heat-balance integral method, we also develop a semi-analytical solution, which agrees well with the numerical solution. We construct a space of dimensionless groups for the basin and perform a systematic exploration of this space to illustrate the influence of each group on the shoreline trajectory. Our model results suggest that all subsiding fluvio-deltaic basins exhibit a standard autoretreat shoreline trajectory in which a brief period of shoreline advance is followed by an extended period of shoreline retreat. Base-level cycling produces a shoreline response that varies relative to the autoretreat signal. Contrary to previous studies, we fail to observe either a strong phase shift between shoreline and base level or a pronounced attenuation of the amplitude of shoreline response as the frequency of base-level cycling decreases. However, the amplitude of shoreline response to base-level cycling is a function of the basin's age.