The structure of momentum and concentration boundary layers developing over a bed of Potamocorbula amurensis clam mimics was studied. Laser Doppler velocimetry (LDV) and laser-induced fluorescence (LIF) probes were used to quantify velocity and concentration profiles in a laboratory flume containing 3969 model clams. Model clams incorporated passive roughness, active siphon pumping, and the abi...

A perturbation model for high-frequency sound scattering from an irregular elastic sea bed is considered. The sea bed is assumed homogeneous on the average and two kinds of irregularities are assumed to cause scattering: roughness of the water-sea bed interface and volume inhomogeneities of the sediment mass density and the speeds of compressional and shear waves. The first-order small perturba...

in this paper twelve different empirical resistance coefficients expressed in terms of manning's roughness are used apiece in seventeen known compositing methods. the data obtained from ten different cross-sections of the sefidrood river, iran, are used for the evaluation of the empiricalformulas. the present case-study is selected from a reach with gravel bed topology. then no remarkable bed f...

Two-choice tests were conducted to examine the effect of surface roughness on the resting preference of bed bugs, Cimex lectularius L., on copper, basswood, and acrylic materials. The influence of pyrethroid formulation applications on resting preferences was also evaluated. Bed bugs were given the choice of resting between two sanded halves of each material tested. One half was sanded with a P...

Large-eddy simulations of free surface flow over bed-mounted square bars are performed for laminar, transitional and turbulent flows at constant Froude number. Two different bar spacings selected corresponding to k-type (reattaching flow) roughness, respectively. The validated with experimental data convincing agreement between simulation measurement is obtained in terms water elevations stream...

We compare measured profiles of upper layer shear and rates of kinetic energy dissipation with the predictions of a one-dimensional turbulence model proposed by Craig and Banner (1994). Their formulation contains an unknown parameter, the "roughness length" z0, which we determine by fitting computed and observed dissipation rates. The resulting model, without further adjustment, is then used to...

Abstract Palaeo-glacial landforms can give insights into bed roughness that currently cannot be captured underneath contemporary-ice streams. A few studies have measured of palaeo-ice streams but the specific landform assemblages has not been assessed. If glacial a characteristic bed-roughness signature, this could potentially used to constrain where certain exist sheets. To test this, was calc...

Understanding bed load transport fluctuations in rivers is crucial for development of a transport theory and for choosing a sampling interval for “mean” transport rates. Field-scale studies lack sufficient resolution to statistically characterize these fluctuations, while laboratory experiments are limited in scale and hence cannot be directly compared to field cases. Here we use a natural-scal...

Include a brief (<300 words) abstract, by itself, on p.2. Abstracts may not be published in the printed book but will be used in review and editing and may be used in web presentations of the book contents. Understanding and quantifying the co-evolution of migrating bed topography and flow turbulence is crucial for characterizing sediment transport in alluvial rivers. The self-organized bed for...