AvaFrame <i>com1DFA</i> (v1.3): a thickness-integrated computational avalanche module – theory, numerics, and testing

Abstract

Simulation tools are important to investigate and predict mobility and the destructive potential of gravitational mass flows (e.g., snow avalanches). AvaFrame – the open avalanche framework – offers well-established computational modeling approaches, tools for data handling and analysis, and ready-to-use modules for evaluation and testing. This paper presents the theoretical background, derivation, and model verification for one of AvaFrame's core modules, the thickness-integrated computational model for avalanches with flow or mixed form of movement, named com1DFA. Particular emphasis within the description of the utilized numerical particle–grid method is given to the computation of spatial gradients and the accurate implementation of driving and resisting forces. The implemented method allows us to provide a time–space criterion connecting the numerical particles, grid, and time discretization. The convergence and robustness of the numerical implementation is checked with respect to the spatiotemporal evolution of the flow variables using tests with a known analytical solution. In addition, we present a new test for verifying the accuracy of the numerical simulation in terms of runout (angle and distance). This test is derived from the total energy balance along the center-of-mass path of the avalanche. This article, particularly in combination with the code availability (open-source code repository) and detailed online documentation provides a description of an extendable framework for modeling and verification of avalanche simulation tools.