نتایج جستجو برای: bagnold

تعداد نتایج: 81  

Journal: :Physical review. E, Statistical, nonlinear, and soft matter physics 2008
Robert Brewster Leonardo E Silbert Gary S Grest Alex J Levine

The validity of the Bagnold constitutive relation in gravity-driven granular flow down an inclined plane is studied by discrete element (DEM) simulations. In the limit of infinitely hard particles, the Bagnold relation is known to hold exactly. We determine deviations from this relation as a function of all parameters governing interparticle interactions. These include elastic compliance, inela...

2017
B L Ehlmann K S Edgett B Sutter C N Achilles M L Litvak M G A Lapotre R Sullivan A A Fraeman R E Arvidson D F Blake N T Bridges P G Conrad A Cousin R T Downs T S J Gabriel R Gellert V E Hamilton C Hardgrove J R Johnson S Kuhn P R Mahaffy S Maurice M McHenry P-Y Meslin D W Ming M E Minitti J M Morookian R V Morris C D O'Connell-Cooper P C Pinet S K Rowland S Schröder K L Siebach N T Stein L M Thompson D T Vaniman A R Vasavada D F Wellington R C Wiens A S Yen

The Mars Science Laboratory Curiosity rover performed coordinated measurements to examine the textures and compositions of aeolian sands in the active Bagnold dune field. The Bagnold sands are rounded to subrounded, very fine to medium sized (~45-500 μm) with ≥6 distinct grain colors. In contrast to sands examined by Curiosity in a dust-covered, inactive bedform called Rocknest and soils at oth...

Journal: :Physical review. E, Statistical, nonlinear, and soft matter physics 2005
Robert Brewster Gary S Grest James W Landry Alex J Levine

Cohesive granular media flowing down an inclined plane are studied by discrete element simulations. Previous work on cohesionless granular media demonstrated that within the steady flow regime where gravitational energy is balanced by dissipation arising from intergrain forces, the velocity profile in the flow direction scales with depth in a manner consistent with the predictions of Bagnold. H...

Journal: :Physical review letters 2007
Leonardo E Silbert Gary S Grest Robert Brewster Alex J Levine

We study the rheology and distribution of interparticle contact lifetimes for gravity-driven, dense granular flows of noncohesive particles down an inclined plane using large-scale, three dimensional, granular dynamics simulations. Rather than observing a large number of long-lived contacts as might be expected for dense flows, brief binary collisions predominate. In the hard-particle limit, th...

2017
M. G. A. Lapotre B. L. Ehlmann S. E. Minson R. E. Arvidson R. C. Ewing Mathieu Lapotre

During its ascent up Mount Sharp, the Mars Science Laboratory Curiosity rover traversed the Bagnold Dune Field. We model sand modal mineralogy and grain size at four locations near the rover traverse, using orbital shortwave infrared single scattering albedo spectra and a Markov-Chain Monte Carlo implementation of Hapke’s radiative transfer theory to fully constrain uncertainties and permitted ...

2001
Alexander V. Potapov Melany L. Hunt Charles S. Campbell

Ž . This study presents a computational method combining smoothed particle hydrodynamics SPH and the discrete element method Ž . DEM to model flows containing a viscous fluid and macroscopic solid particles. The two-dimensional numerical simulations are validated by comparing the wake size, drag coefficient and local heat transfer for flow past a circular cylinder at Reynolds numbers near 100. ...

Journal: :journal of rangeland science 2011
nazila sedaei afshin honarbakhsh sayyed farhad mousavi

in this paper, two formulas were chosen among those that estimate the suspendedsediment discharge in rivers. these two formulas were lane and kalinske and bagnold. forstudying and knowing the correlation between input parameters and calculated suspendedsediment discharge (cssd), the spss17 software was used. input parameters in these twoformulas were as: water velocity, water discharge, suspend...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 1976
L B Leopold W W Emmett

A bedload trap in the riverbed provided direct quantitative measurement of debris-transport rate in the East Fork River, Wyoming, a basin of 466 km(2) drainage area. Traction load moves only during the spring snow melt season. Data collected in three spring runoff seasons during which a peak flow of 45 m(3)/s occurred showed that transport rate is correlated with power expenditure of the flowin...

1999
Vincenzo D’Agostino Mario A. Lenzi

Sediment transport is monitored by a specially designed instrumentation installed on a steep Ž . mountain streams the Rio Cordon . The variability of bedload rate and yield reflects the Ž . variability in flow discharge. Bedload and flow data for ‘ordinary’ low peak flow floods and ‘exceptional’ sediment transport events are used to test the range of application of the bedload equations propose...

Journal: :journal of water sciences research 2012
n sedaei a kavian

predictions of suspended sediment load for soolegan river, iran using selected empirical equ-ations were made based on 355 data sets. data include flow discharges from 3.11 m3/s to 43.81 m3/s, flow velocities from 0.22 m/s to 1.03 m/s, and flow depths from 0.5 to 1.03 m. equations of einstein (1950), bagnold (1966), toufalleti (1968), brooks (1963), chang-simons-richardson(1965),lane-kalinske (...

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