Analytical and numerical solution of a generalized Stefan problem exhibiting two moving boundaries with application to ocean delta formation

作者：Lorenzo Trueba J; Voller V R^*

来源：Journal of Mathematical Analysis and Applications, 2010, 366(2): 538-549.

DOI：10.1016/j.jmaa.2010.01.008

• Stefan problem
• Dual moving boundaries
• Sediment delta
• Enthalpy solution
• Similarity solution

A model associated with the formation of sedimentary ocean deltas is presented. This model is a generalized one-dimensional Stefan problem bounded by two moving boundaries, the shoreline and the alluvial-bedrock transition. The sediment transport is a non-linear diffusive process: the diffusivity modeled as a power law of the fluvial slope. Dimensional analysis shows that the first order behavior of the moving boundaries is determined by the dimensionless parameter 0 <= R(ab) <= 1-the ratio of the fluvial slope to bedrock slope at the alluvial-bedrock transition. A similarity form of the governing equations is derived and a solution that tracks the boundaries obtained via the use of a numerical ODE solver; in the cases where the exponent theta in the diffusivity model is zero (linear diffusion) or infinite, closed from Solutions are found. For the full range of the diffusivity exponents. 0 <= theta -> infinity, the similarity solution shows that when R(ab) < 0.4 there is no distinction in the predicted speeds of the moving boundaries. Further, within the range of physically meaningful values of the diffusivity exponent, i.e., 0 <= theta similar to 2, reasonable agreement in predictions extents up to R(ab) similar to 0.7. In addition to the similarity solution a fixed grid enthalpy like solution is also proposed; predictions obtained with this solution closely match those obtained with the similarity solution.

• 出版日期2010-6-15