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INCIPIENT MOTION OF NON-COHESIVE SEDIMENT UNDER ICE COVER-AN EXPERIMENTAL STUDY

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Journal of Hydrodynamics 2008年第1期20卷 117-124页

作者： WANG Jun SUI Jue-yi karney bryan W. School of Civil Engineering Hefei University of Technology Hefei 230009 China Environmental Science and Environmental Engineering Program University of Northern British ColumbiaBritish Columbia Canada V2N 4Z9 Department of Civil Engineering University of Toronto Toronto Ontario Canada M5S 1A4

Based on a series of experiments under both ice-covered and free surface conditions, the present article discusses the role of flow velocity and critical shear Reynolds number for incipient motion of bed material. The influence of the resistance coefficients of both the underside of the ice cover and the channel bed on the location of the maximum velocity has been discussed. In addition, the impacts of ice and composite resistance coefficients on flow velocity for incipient motion of bed material have been assessed. The diagram describing the critical shear Reynolds number and the dimensionless shear stress for the incipient motion of sediment under ice covered conditions with different under cover resistance coefficient has been established. The effects of grain size on densimetric Froude number for incipient motion of bed material have been investigated. A relationship between the densimetric Froude number for incipient motion of bed material and the median grain size of bed material as well as the roughness coefficient of channel bed and roughness coefficient of ice cover has been established.

关键词： densimetric Froude number grain size ice cover incipient motion resistance coefficient shear Reynolds number,velocity

EFFECTS OF RIVER ICE ON STAGE-DISCHARGE RELATIONSHIPS——A CASE STUDY OF THE YELLOW RIVER

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International Journal of Sediment Research 2007年第4期22卷 263-272页

作者： Ronald THRING bryan W. karney Prof. Environmental Engineering University of Northern British Columbia 3333 University Way Prince George BC Canada V2N 4Z9 Prof. Department of Civil Engineering University of Toronto 35 St. George Street Toronto ON Canada M5S 1A4

Using field observations at four gauging stations along the Inner Mongolia Reach of the Yellow River in China, this paper explores effects of the ice on the hydraulics of this river reach for four different conditions, namely: under open channel flow, during ice-running period, the ice-covered period, and the river break-up period. The rating curves were found to be well recognized under open channel situations, but were sometimes poorly defined and extremely variable under ice conditions. The results also show that the water level is insensitive to flowing ice prior to freeze-up. However, significant, but hardly surprising, variations were observed during ice-covered conditions. The rating curves for both the ice covered condition and river ice breakup period are developed and some related hydraulic issues are examined. Additionally, the impacts of the ice accumulation and associated riverbed deformation during ice period on the rating curves are discussed.

关键词： Ice-running period Ice covered period Rating curve Riverbed deformation River ice break-up

Numerical modeling of the effects of roughness on flow and eddy formation in fractures

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Journal of Rock Mechanics and Geotechnical Engineering 2017年第1期9卷 105-115页

作者： Scott Briggs bryan W. karney Brent E. Sleep University of Toronto Toronto M5S 1A4 Canada

The effect of roughness on flow in fractures was investigated using lattice Boltzmann method(LBM).Simulations were conducted for both statistically generated hypothetical fractures and a natural dolomite fracture. The effect of increasing roughness on effective hydraulic aperture, Izbash and Forchheimer parameters with increasing Reynolds number(Re) ranging from 0.01 to 500 was examined. The growth of complex flow features, such as eddies arising near the fracture surface, was directly associated with changes in surface roughness. Rapid eddy growth above Re values of 1, followed by less rapid growth at higher Re values, suggested a three-zone nonlinear model for flow in rough fractures. This three-zone model, relating effective hydraulic conductivity to Re, was also found to be appropriate for the simulation of water flow in the natural dolomite fracture. Increasing fracture roughness led to greater eddy volumes and lower effective hydraulic conductivities for the same Re values.

关键词： Hydrogeology Fracture flow Fracture roughness Computational fluid dynamics Lattice Boltzmann method(LBM)

Numerical modelling of flow and transport in rough fractures

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Journal of Rock Mechanics and Geotechnical Engineering 2014年第6期6卷 535-545页

作者： Scott Briggs bryan W.karney Brent E.Sleep University of Toronto Toronto M5S 1A4 Canada

Simulation of flow and transport through rough walled rock fractures is investigated using the latticeBoltzmann method （LBM） and random walk （RW）, respectively. The numerical implementation isdeveloped and validated on general purpose graphic processing units （GPGPUs）. Both the LBM and RWmethod are well suited to parallel implementation on GPGPUs because they require only next-neighbourcommunication and thus can reduce expenses. The LBM model is an order of magnitude faster onGPGPUs than published results for LBM simulations run on modern CPUs. The fluid model is verified forparallel plate flow, backward facing step and single fracture flow; and the RWmodel is verified for pointsourcediffusion, Taylor-Aris dispersion and breakthrough behaviour in a single fracture. Both algorithmsplace limitations on the discrete displacement of fluid or particle transport per time step to minimise thenumerical error that must be considered during implementation. 2014 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.

关键词： Hydrogeology Fracture flow Solute transport Computational fluid dynamics Lattice Boltzmann method(LBM) Random walk(RW)