A coupled debris flow–turbidity current model

Drago, Michele

doi:10.1016/s0029-8018(02)00008-2

Cited by 23 publications

(13 citation statements)

References 8 publications

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“…The turbulent flow model has been described in Drago (2002) and Drago and Terenzi (2001). It is a 2D hydrodynamic model with variable density depending on the sediment concentration and a K 2 l turbulence closure model based on the Mellor and Yamada (1982) formulation.…”

Section: Turbulent Flow Modelmentioning

confidence: 99%

“…Hereafter, only the coupling of the dense flow/turbulent flow models (i.e. the bottom boundary conditions of the turbulent flow model) is described; for a complete description of the turbulent flow model, the reader is referred to Drago (2002). Drago (2002) also describes the coupling of the turbulent flow model with a debris flow model based on a Bingham rheology (Jiang & Le Blond, 1993;Liu & Mei, 1989) in order to simulate the generation of a turbulent flow due to the occurrence of a debris flow.…”

Section: Turbulent Flow Modelmentioning

confidence: 99%

“…However, very few authors tried to couple numerical models of different flow types in order to provide a more complete description of the downcurrent flow transformations and sediment distribution (see, for example, Drago (2002), on the transition from a cohesive debris flow to a turbulent flow).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Modelling subaqueous bipartite sediment gravity flows on the basis of outcrop constraints: first results

Tinterri

Drago

Consonni

et al. 2003

Marine and Petroleum Geology

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Section: Turbulent Flow Modelmentioning

confidence: 99%

Section: Turbulent Flow Modelmentioning

confidence: 99%

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Modelling subaqueous bipartite sediment gravity flows on the basis of outcrop constraints: first results

Tinterri

Drago

Consonni

et al. 2003

Marine and Petroleum Geology

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“…Concerning the first issue, there seems to be a consensus that many turbidity currents are generated by debris flows, yet very little work has been done to quantify this process and to understand and model the downstream variation of deposit composition (Drago, 2002;Tinterri et al, 2003). Laboratory experiments with sand-rich sediment mixtures combining the experimental techniques of Mohrig and Marr (2003) with those described here should be very fruitful for understanding the relevant processes in turbidity-current formation and for scaling the results from the laboratory to the continental margin.…”

Section: Introductionmentioning

confidence: 99%

Emerging insights into the dynamics of submarine debris flows

Elverhøi¹,

Issler

Blasio

et al. 2005

Nat. Hazards Earth Syst. Sci.

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Recent experimental and theoretical work on the dynamics of submarine debris flows is summarized. Hy-droplaning was first discovered in laboratory flows and later shown to likely occur in natural debris flows as well. It is a prime mechanism for explaining the extremely long runout distances observed in some natural debris flows even of over-consolidated clay materials. Moreover, the accelerations and high velocities reached by the flow head in a short time appear to fit well with the required initial conditions of observed tsunamis as obtained from back-calculations. Investigations of high-speed video recordings of laboratory debris flows were combined with measurements of total and pore pressure. The results are pointing towards yet another important role of ambient water: Water that intrudes from the water cushion underneath the hydroplaning head and through cracks in the upper surface of the debris flow may drastically soften initially stiff clayey material in the "neck" of the flow, where significant stretching occurs due to the reduced friction at the bottom of the hydroplaning head. This self-reinforcing process may lead to the head separating from the main body and becoming an "outrunner" block as clearly observed in several natural debris flows. Comparison of laboratory flows with different material composition indicates a gradual transition from hydroplaning plug flows of stiff clay-rich material, with a very low suspension rate, to the strongly agitated flow of sandy materials that develop a pronounced turbidity current. Statistical analysis of the great number of distinguishable lobes in the Storegga slide complex reveals power-law scaling behavior of the runout distance with the release mass over many orders of magnitude. Mathematical flow models based on viscoplastic material behavior (e.g. BING) successfully reproduce the observed scaling behavior only for relatively small clay-rich debris flows while granular (frictional) models fail at all scales. For very large release masses, hydroplan-ing or significant softening of the shear layer due to water in-Correspondence to: A. Elverhøi (anders.elverhoi@geo.uio.no) corporation must be invoked to recover the observed scaling behavior; a combination of both effects likely will give the most realistic description of the phenomenon. Detailed studies of the neck behavior and the compositional dependence of the material properties are needed to arrive at a quantitative model. Other related and important open questions concern the rheological model appropriate for sandy debris flows and the suspension rate from the dense body into the associated turbidity current.

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“…Hence DSESS does not currently represent conditions well on steep slopes where such debris flows become important (Blair and McPherson, 1994;Edwards et al, 1997;Collinson, 1996;Blair, 1999c). Future versions of DSESS will include representations of debris flow dynamics, using the results of Imran et al (2001), DAmbrosio et al (2002), Drago (2002) and, particularly, Franzi (2002.…”

Section: Details Of the Model Calculationsmentioning

confidence: 99%

A model for simulating the deposition of water-lain sediments in dryland environments

Bunch

Mackay

Tellam

et al. 2004

Hydrol. Earth Syst. Sci.

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A numerical process-imitating model, the Discrete Storm Event Sedimentation Simulator (DSESS), has been developed to represent the climatic and hydraulic conditions of drylands in modelling their geomorphological development and sedimentary facies distributions. The ultimate aim is to provide insights into the lateral variability of permeability in the Triassic Sandstone aquifers of the UK for the study of solute movement. DSESS employs discrete storm-flood automata, released across a cellular landscape, to model sediment transport: erosion, migration and deposition. Sediment classes with different grain sizes can be modelled. Empirical process-based equations are used to quantify the movement of the automata, their erosion potential, sediment-carrying capacity and interaction with the underlying sediments. The approach emphasises the sequence of dryland storm events and associated floods rather than their timing. Flood events are assumed to be discrete in time. Preliminary tests carried out with DSESS using simple systems and idealised initial conditions produce lithological and land surface features characteristic of dryland settings and indicate the potential of the model for large-scale, long-term modelling of sedimentary facies development. Markedly different results are observed across the range of tests carried out in response to the non-linear interactions between the different elements of the landscape and the floodwaters simulated with DSESS. Simulations show that sediment accumulations develop concave upward radial profiles, plano-convex cross-profiles and possess a general lateral grading of sediment with distance from source. The internal grain size architecture shows evidence of both persistent and rapidly changing flow conditions, with both lateral and longitudinal stepping of coarse bodies produced by scour and fill events and random avulsions. Armoured layers form so that near-surface sediments have increased likelihood of preservation. Future developments will include representation of aeolian deposition, mass wasting and hyperconcentrated (debris) flows.

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A coupled debris flow–turbidity current model

Cited by 23 publications

References 8 publications

Modelling subaqueous bipartite sediment gravity flows on the basis of outcrop constraints: first results

Modelling subaqueous bipartite sediment gravity flows on the basis of outcrop constraints: first results

Emerging insights into the dynamics of submarine debris flows

A model for simulating the deposition of water-lain sediments in dryland environments

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