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.

碎屑流代表沉积物颗粒混合物的重力驱动流，并在陡峭的斜坡上水。尽管过去几十年来建模和计算地球物理质量流的发展，但这种固体富集多相流的预测仍然是最具挑战性的主题之一，主要是在两个方面（i）理论建模和（ii）高阶数值方法。一方面，在大多数连续模型中，碎屑流通常被视为单相介质，即使碎屑流显然是混合物。在这种单相方法中，碎屑混合物被视为一种非牛顿流体，包括某些塑料行为，也可以作为库仑连续体，其中孔隙流体的作用可以参数化或具有相同组成速度的混合物。构建非常罕见的多含量模型并将其应用于碎屑流。属于这种方法的一些现有模型包括各种弱点。它们的热力学一致性通常不验证或不满足。另一方面，关于数值方法，通常采用了经典的数值技术，其中离散化的准确性不可避免地会在局部极端降低到第一阶。高分辨率TVD（总变化减少）方案也是如此。通过这个项目，我们将尝试开发一种热力学一致的混合模型，该模型通过剥削熵原理来描述流动的颗粒流体混合物。自2008年自2008年以来正在开发的高度准确的不连续的Galerkin软件库Boss（有限的支持频谱求解器）将在多个基质混合物问题方面扩展，以数值检查颗粒状流体混合物的流量。碎屑将沿倾斜的平面往下流入水平跳出区域，尤其是遇到障碍物。