Interaction of two-phase debris flow with obstacles

Kattel, Parameshwari; Kafle, Jeevan; Fischer, Jan-Thomas; Mergili, Martin; Tuladhar, Bhadra Man; Pudasaini, Shiva P.

doi:10.1016/j.enggeo.2018.05.023

Cited by 109 publications

(40 citation statements)

References 52 publications

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“…So the fluid material generates an envelope at the sides and the front of the solid and/or fine‐solid dominated central surge of the debris mixture. Such behaviors are also observed in solid‐fluid mixture mass flows (Kattel et al, ). In the simulation G with 90% solid and 10% fluid, a clear fan and frontal surge and lobe is developed.…”

Section: Benchmark Numerical Simulationsmentioning

confidence: 57%

A Multi‐Phase Mass Flow Model

2019

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Geomorphic mass flows are often complex in terms of material composition and its evolution in space and time. The simulation of those hazardous phenomena would strongly benefit from a multi‐phase model, considering the motion and—importantly—interaction of phases characterized by different physical aspects including densities, frictions, viscosities, fractions, and their mechanical responses. However, such a genuine multi‐phase model is still lacking. Here, we present a first‐ever, multi‐mechanical, multi‐phase mass flow model composed of three different phases: the coarse solid fraction, fine‐solid fraction, and viscous fluid. The coarse solid component, called solid, represents boulders, cobbles, gravels, or blocks of ice. Fine‐solid represents fine particles and sand, whereas water and very fine particles, including colloids, silt, and clay, constitute the viscous fluid component in the mixture. The involved materials display distinct mechanical responses and dynamic behaviors. Therefore, the solid, fine‐solid, and fluid phases are described by Coulomb‐plastic, shear‐ and pressure‐dependent plasticity‐dominated viscoplastic, and viscosity‐dominated viscoplastic rheologies. They are supposed to best represent those materials. The new model is flexible and addresses some long‐standing issues of multi‐phase mass flows on how to reliably describe the flow dynamics, runout, and deposition morphology of such type of phenomena. With reference to some benchmark simulations, the essence of the model and its applicability are discussed.

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Section: Benchmark Numerical Simulationsmentioning

confidence: 57%

A Multi‐Phase Mass Flow Model

2019

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“…Although these simulations agreed well with the proposed theory concerning the impact, they were mainly carried out for dry granular flows with no consideration of fluid presence. Such presence would change the flow characteristics and the time history of its applied pressure (Vollmöller, 2004;Kattel et al, 2018). Other models based on the discrete element method (DEM) accounted for the presence of fluid by coupling a DEM with either a LBM (lattice Boltzmann method) or a CFD (computational fluid dynamics) solver (Leonardi et al, 2016;Ding and Xu, 2018).…”

Section: Introductionmentioning

confidence: 99%

Numerical modeling using an elastoplastic-adhesive discrete element code for simulating hillslope debris flows and calibration against field experiments

Albaba

Schwarz

Wendeler

et al. 2019

Nat. Hazards Earth Syst. Sci.

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Abstract. This paper presents a discrete-element-based elastoplastic-adhesive model which is adapted and tested for producing hillslope debris flows. The numerical model produces three phases of particle contacts: elastic, plastic and adhesive. A parametric study was conducted investigating the effect of model parameters and inclination angle on flow height, velocity and pressure, in order to define the most sensitive parameters to calibrate. The model capabilities of simulating different types of cohesive granular flows were tested with different ranges of flow velocities and heights. The basic model parameters, the microscopic basal friction (ϕb) and ratio between stiffness parameters k1/k2, were calibrated using field experiments of hillslope debris flows impacting a pressure-measuring sensor. Simulations of 50 m3 of material were carried out on a channelized surface that is 41 m long and 8 m wide. The calibration process was based on measurements of flow height, flow velocity and the pressure applied to a sensor. Results of the numerical model matched those of the field data in terms of pressure and flow velocity well while less agreement was observed for flow height. Those discrepancies in results were due in part to the deposition of material in the field test, which is not reproducible in the model. Results of best-fit model parameters against selected experimental tests suggested that a link might exist between the model parameters ϕb and k1/k2 and the initial conditions of the tested granular material (bulk density and water and fine contents). The good performance of the model against the full-scale field experiments encourages further investigation by conducting lab-scale experiments with detailed variation in water and fine content to better understand their link to the model's parameters.

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“…Ostacle interactions are mostly discussed for granular flows [6,38,40,43], or for a debris bulk [7,31,44] without considering two separate phases. Kattel et al [24] performed a number of computational experiments to present detailed dynamical interactions of the flowing debris mass with stationary tetrahedral obstacles mounted on a generic slope topography that merges to horizontal run out plane. They described the run out scenarios for solid and fluid phases separately and for a debris bulk as a whole for tetrahedral obstacles.…”

Section: Introductionmentioning

confidence: 99%

“…They described the run out scenarios for solid and fluid phases separately and for a debris bulk as a whole for tetrahedral obstacles. Employing the same model, Kattel and Tuladhar [23] performed numerical experiments on obstruction and contraction ratio of two-phase debris flow due to converging lateral shear walls. Kafle et al [20] presented first-ever three-dimensional, high-resolution simulation results for a two-phase landslide impacting a fluid reservoir installed with obstacles of different shapes, sizes, numbers, and at different positions on the subaerial slopes and bathymetry.…”

Section: Introductionmentioning

confidence: 99%

Simulations for Flow-Symmetry Through r.avaflow in the General Two-Phase Mass Flow Model

Kafle

Kattel

2019

J. Nep. Math. Soc.

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Gravitational flows, e.g., landslide, debris flow and avalanches are hazardous mass wasting processes. The proper understanding of their dynamics is very important. As laboratory experiments can not perfectly model their initiation process and field assess of the live events are very difficult, numerical experiments have become the promising way for the study of their flow dynamics. Here we employ the enhanced version of two-phase mass flow model [33] through the open source computational code, r.avaflow to analyze the issue of symmetry in the flow. Two-phase debris mass are triggered from all the flanks of the three different pyramids (triangle-based, square-based and octagon-based) with different rotational symmetry and study the flow pattern along with maximum kinetic energy of the flow. Flow past two different types of obstacles (a tetrahedron and a square based pyramid) are also observed. The possible causes of asymmetry in the flow are also analyzed.

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Interaction of two-phase debris flow with obstacles

Cited by 109 publications

References 52 publications

A Multi‐Phase Mass Flow Model

A Multi‐Phase Mass Flow Model

Numerical modeling using an elastoplastic-adhesive discrete element code for simulating hillslope debris flows and calibration against field experiments

Simulations for Flow-Symmetry Through r.avaflow in the General Two-Phase Mass Flow Model

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