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Continuum mechanical modeling and higher-order accurate simulation of debris flows

泥石流连续体力学建模与高阶精确模拟

基本信息

批准号：
262376695
负责人：
Professor Dr.-Ing. Yongqi Wang
金额：
--
依托单位：
Versuchsanstalt für Wasserbau, Hydrologie und Glaziologie
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2015
资助国家：
德国
起止时间：
2014-12-31 至 2019-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/262376695?language=en
关键词：
Continuum mechanical modeling higher order

项目摘要

A debris flow represents gravity-driven flow of a mixture of sediment particles and water down a steep slope. Despite the development in modeling and computing geophysical mass flows in the past decades, the prediction of such solid-fluid multiphase flows is still one of the most challenging topics mainly in two aspects (i) theoretical modeling and (ii) higher-order numerical methods. On the one hand, in most continuum models, the debris flows are often treated as a single-phase medium, even though a debris flow is clearly a mixture. In such single-phase approaches, the debris mixture is considered either as a non-Newtonian fluid including some plastic behavior or as a Coulomb continuum where the role played by the pore fluid can be incorporated parametrically or as a mixture with the same constituent velocities. Very rare multi-constituent models are constructed and applied to debris flows. A few existing models belonging to this approach include various weaknesses. Their thermodynamic consistency is usually either not verified or not satisfied. On the other hand, regarding numerical methods, often classical numerical techniques are employed in which the accuracy of a discretization inevitably degrades to the first order at local extreme. This is also the case for high-resolution TVD (total variation diminishing) schemes. With this project, we will attempt to develop a thermodynamically consistent mixture model describing flowing granular-fluid mixtures by means of the exploitation of the entropy principle. The highly accurate discontinuous Galerkin software library BoSSS (Bounded Support Spectral Solver), which is under development since 2008 in our institute, will be extended with regard to multi-constituent mixture problems, to numerically examine flows of granular-fluid mixtures. Debris flows down an inclined plane merging into a horizontal run-out zone, especially encountering obstacles will be investigated.

泥石流是由泥沙颗粒和水的混合物在重力作用下沿陡坡向下流动而形成的。尽管在过去的几十年中，在模拟和计算地球物理质量流的发展，这种固体-流体多相流的预测仍然是最具挑战性的课题之一，主要在两个方面（i）理论建模和（ii）高阶数值方法。一方面，在大多数连续介质模型中，泥石流通常被视为单相介质，即使泥石流显然是一种混合物。在这种单相方法中，碎片混合物被认为是一种非牛顿流体，包括一些塑性行为，或作为一个库仑连续的孔隙流体所发挥的作用，可以参入或作为具有相同的组分速度的混合物。非常罕见的多组分模型构建和应用于泥石流。属于这种方法的一些现有模型存在各种缺陷。它们的热力学一致性通常没有得到验证或不令人满意。另一方面，关于数值方法，通常采用经典的数值技术，其中离散化的精度不可避免地在局部极值处降低到一阶。这也是高分辨率TVD（总变差递减）计划的情况。在这个项目中，我们将试图通过利用熵原理来开发一个描述流动颗粒-流体混合物的物理相容的混合物模型。自2008年以来，我们研究所正在开发的高精度不连续Galerkin软件库BoSSS（有界支持谱求解器）将扩展到多组分混合物问题，以数值研究颗粒流体混合物的流动。泥石流沿斜面向下流入水平流出区，特别是遇到障碍物时，将进行研究。