Multi-Mesh-Scale Approximation of Thin Geophysical Mass Flows on Complex Topographies

Multi-Mesh-Scale Approximation of Thin Geophysical Mass Flows on Complex Topographies

Year:    2021

Author:    Yih-Chin Tai, Jeaniffer Vides, Boniface Nkonga, Chih-Yu Kuo

Communications in Computational Physics, Vol. 29 (2021), Iss. 1 : pp. 148–185

Abstract

This paper is devoted to a multi-mesh-scale approach for describing the dynamic behaviors of thin geophysical mass flows on complex topographies. Because the topographic surfaces are generally non-trivially curved, we introduce an appropriate local coordinate system for describing the flow behaviors in an efficient way. The complex surfaces are supposed to be composed of a finite number of triangle elements. Due to the unequal orientation of the triangular elements, the distinct flux directions add to the complexity of solving the Riemann problems at the boundaries of the triangular elements. Hence, a vertex-centered cell system is introduced for computing the evolution of the physical quantities, where the cell boundaries lie within the triangles and the conventional Riemann solvers can be applied. Consequently, there are two mesh scales: the element scale for the local topographic mapping and the vertex-centered cell scale for the evolution of the physical quantities. The final scheme is completed by employing the HLL-approach for computing the numerical flux at the interfaces. Three numerical examples and one application to a large-scale landslide are conducted to examine the performance of the proposed approach as well as to illustrate its capability in describing the shallow flows on complex topographies.

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Journal Article Details

Publisher Name:    Global Science Press

Language:    English

DOI:    https://doi.org/10.4208/cicp.OA-2019-0184

Communications in Computational Physics, Vol. 29 (2021), Iss. 1 : pp. 148–185

Published online:    2021-01

AMS Subject Headings:    Global Science Press

Copyright:    COPYRIGHT: © Global Science Press

Pages:    38

Keywords:    Multi-mesh-scale approach complex topography shallow flows unstructured mesh vertex-centered formulation.

Author Details

Yih-Chin Tai

Jeaniffer Vides

Boniface Nkonga

Chih-Yu Kuo