Modeling and 2-D FE-simulation of Vortex Ripples Using a Three-phase Mixture Approach

T. Reisner[1], H. Steeb[1], and J. Renner[2]
[1]Institute of Mechanics - Continuum Mechanics, Ruhr-University Bochum, Bochum, Germany
[2]Institute of Geology, Mineralogy and Geophysics, Ruhr-University Bochum, Bochum, Germany

A new continuum-mechanical model for the study of sediment erosion, transport and deposition was developed using a three-phase mixture approach. It differs from existing two-phase models in that the sediment is modeled as two different phases, rigid sediment bed and mobile particles, instead of one phase.

The model is currently implemented into Comsol Multiphysics using the Mixture Model and PDE interfaces. Numerical obstacles are the high nonlinearity and strong coupling of the equations. Results using stabilized Navier-Stokes equations in a ripple-like geometry are in good agreement with the flow pattern around real ripples in experiments. The model should provide an improved understanding of ripple formation, but also sediment erosion, transport and deposition processes in general.