Titlebook: Aeolian Grain Transport 1; Mechanics Ole E. Barndorff-Nielsen,Brian B. Willetts Conference proceedings 1991 Springer-Verlag Wien 1991 Sedim

青石板

锉屑

Saltation layers, vegetation canopies and roughness lengthse fluid). Therefore, information on turbulence and momentum transfer in vegetation canopies provides guidance for turbulence in saltation layers. Working from the simplest gradient-diffusion theory for momentum transfer known to be useful in vegetation canopies, the paper explores a first-order theo

poliosis

Grain transport rates in steady and unsteady turbulent airflowsere made at one second intervals to assess mass-flux response to velocity variations. Resulting grain flux and velocity series demonstrate the variability concealed by conventional time-averaged data. In steady tunnel winds, time-dependent mass transport rates are found to correlate better with fluc

Fsh238

Initiation of motion of quartz sand grainst disturbed grains usually, but not always, roll before taking off into reptation or saltation. Time-averaged description of the population of initial motions is deficient because of the importance of pronounced flurries of grain activity which occur at intervals. The flurries are clearly associated

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高贵领导

An experimental study of Froude number effect on wind-tunnel saltationette [11] concluded that an independence Froude number criterion did apply to the problem and they estimate, based on wind-tunnel Froude number data ranging from 35 to 80, an independence Froude number value of about 20 for saltating flows to be free of facility constraints imposed on the saltation.

Coterminous

Grain shape effects on aeolian sediment transportmining sediment transport rate. Collision generates more bed activity as sphericity increases, whereas grains with a low sphericity are more readily entrained at slow windspeeds by direct action of the wind. As sphericity decreases grain trajectories become longer and flatter.

acquisition

Two- and three dimensional evolution of granular avalanche flow — theory and experiments revisited with a constant internal angle of friction. Bed resistance is modeled through a sliding law by additively composing the basal traction of a Mohr-Coulomb stress with bed friction angle δ and a viscous drag that is proportional to the first or second power of the sliding velocity. The theoretical mod

Abominate

A review of recent progress in our understanding of aeolian sediment transportck mechanism) is treated in the context of recent modelling of the self-regulating saltation process. The link between saltation and suspension is discussed briefly. We conclude by outlining future research directions that must involve a greater symbiosis of experimentalists and theoreticians, working both at the grain and the bedform scales.

thalamus