Bed Stability of Step‐Pool Channels With Macrorough Sidewalls

Critical stability number in rock lined channels

Fine bed material in pools of natural gravel bed channels

Natural gravel bed channels commonly contain a fine mode of sand and fine gravel that fills voids of the bed framework of coarser gravel. If the supply of fine bed material exceeds the storage capacity of framework voids, excess fine material forms surficial patches, which can be voluminous in pools during low flow. Data collected in 34 natural channels in northern California and southern Orego...

Calculating bed load transport in steep boulder bed channels

[1] Steep, rough channels occupy a large fraction of the total channel length in mountainous regions. Most sediment mobilized on hillslopes must pass through these streams before reaching lower-gradient channels. Steep channels have wide grain size distributions that are composed of finer, more mobile sediment and large, rarely mobile grains. The large grains can bear a significant portion of t...

Large-scale Structure in Rayleigh-BCnard Convection with Impenetrable Sidewalls

In numerical Rayleigh-BCnard convection at Rayleigh number lo5 and 5 x 105, Prandtl numbers 0.07, 0.7, and 7, and aspect ratios 3, 4 or 6, large-scale patterns are sought. For aspect ratio 6 and Pr = 0.7, saturation of the mean velocity is only observed after 20 convective timescales. Three-dimensional visualization shows a strong influence of the confining sidewalls and corners for all Prandtl...

A Linear Stability Analysis of a Homogeneous Fluidized Bed

In this work the local equations governing the dynamics of fluidized beds are written in terms of averaged variables and constitutive relations based on physical arguments are proposed. The averaged equations are perturbed with small disturbances from the homogeneous fluidization state, and linearized with respect to the perturbations. A stability analysis is carried out and shows that the part...