1Department of Environmental Systems Science,
ETH Zentrum, CHN H41, 8092 Zürich, Switzerland
2Helmholtz-Centre Potsdam GFZ
German Research Center for Geosciences,
Telegrafenberg, 14473 Potsdam, Germany
3Swiss Federal Research Institute WSL,
Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
Received: 26 Jun 2015 – Discussion started: 13 Aug 2015
Abstract. Here, we present a three-dimensional fluid dynamic solver that simulates debris flows as a mixture of two fluids (a Coulomb viscoplastic model of the gravel mixed with a Herschel–Bulkley representation of the fine material suspension) in combination with an additional unmixed phase representing the air and the free surface. We link all rheological parameters to the material composition, i.e., to water content, clay content, and mineral composition, content of sand and gravel, and the gravel's friction angle; the user must specify only two free model parameters. The volume-of-fluid (VoF) approach is used to combine the mixed phase and the air phase into a single cell-averaged Navier–Stokes equation for incompressible flow, based on code adapted from standard solvers of the open-source CFD software OpenFOAM. This effectively single-phase mixture VoF method saves computational costs compared to the more sophisticated drag-force-based multiphase models. Thus, complex three-dimensional flow structures can be simulated while accounting for the pressure- and shear-rate-dependent rheology.
Revised: 15 Jul 2016 – Accepted: 18 Jul 2016 – Published: 31 Aug 2016
von Boetticher, A., Turowski, J. M., McArdell, B. W., Rickenmann, D., and Kirchner, J. W.: DebrisInterMixing-2.3: a finite volume solver for three-dimensional
debris-flow simulations with two calibration parameters – Part 1: Model description, Geosci. Model Dev., 9, 2909-2923, doi:10.5194/gmd-9-2909-2016, 2016.