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- Title
A two-phase debris flow model with turbulence.
- Authors
Kafle, Jeevan; Dewals, Benjamin J.; Pudasaini, Shiva P.
- Abstract
Turbulence is an important mechanical aspect that substantially influences the dynamics ofthe complex mass flows. Following Pudasaini and Kafle (2019), here, we extend the generaltwo-phase debris flow model (Pudasaini, 2012), as a mixture of solid particles and viscousfluid, by including the turbulence associated with the fluid-phase. The emergence of theadditional shear stress terms further dissipates the fluid energy stabilizing the fluidcomponent in the mixture, and thus, the mixture as a whole. This helps in numericalsimulation as the fluid component is a source of numerical instability. Based on theBoussineq approximation, we obtain different turbulent stresses. Following Dewals et al.(2008) and Erpicum et al. (2009), the turbulent eddy/kinematic viscosity is modelled in twodifferent ways with RANS. First, we use a simple algebraic turbulent closure. For this, weassume that turbulence is bed dominated which includes the flow depth and theshear velocity. This is reasonable for a shallow flow consideration. Second, a κ - ɛturbulence model is used. Furthermore, for computational efficiency, both the two-phaseturbulent models are reduced from full three-dimensional models to depth-averagedtwo-dimensional models. Resulting models are compared, also with the constant algebraicturbulent closure. Basic analytical and numerical results are presented to highlightthe importance and application potential of the turbulence in two-phase mixtureflows.References:Dewals, B. J., Kantoush, S. A., Erpicum, S., Pirotton, M., Schleiss, A. J. (2008):Experimental and numerical analysis of flow instabilities in rectangular shallow basins.Environmental Fluid Mechanics, 8, 31-54.Erpicum, S., Meile, T., Dewals, B. J., Pirotton, M., Schleiss, A. J. (2009): 2D numerical flowmodeling in a macro-rough channel. International Journal for Numerical Methods in Fluids,61, 1227-1246.Pudasaini, S. P. (2012): A general two-phase debris flow model. J. Geophys. Res. 117,F03010, doi: 10.1029/2011JF002186.Pudasaini, S. P., Kafle, J. (2019): Two-phase debris flow model with turbulence (InPreparation).
- Subjects
TWO-phase flow; TURBULENCE; FLUID mechanics; KINEMATIC viscosity; FLOW instability; EDDY viscosity
- Publication
Geophysical Research Abstracts, 2019, Vol 21, p1
- ISSN
1029-7006
- Publication type
Article