Since L-moment estimators are linear functions of the ordered data values, they are virtually unbiased and have relatively small sampling variance, especially in comparison to the classical coefficients of skewness and kurtosis. Moreover, estimators of L-moments are relatively insensitive to outliers. Liaw and Zheng (2004) calculated drag forces on cylinders by polynomial approximations in whic...

Dispersion of large deformable droplets in turbulent channel flow is investigated: the fluids are considered of same density and viscosity for a broad range of plausible values of surface tension. Droplets much larger than the Kolmogorov length scale are released in a channel flow; the turbulent flow is computed with pseudo-spectral Direct Numerical Simulations (DNS), while phase interactions a...

In [1] and [2] we computed the lift and drag forces on a sphere, subjected to a wall-bounded oscillatory flow. The forces were found as a function of the Reynolds number, the forcing frequency, and the gap between the particle and the ideally smooth rigid bounding wall. Here we investigate how the forces change as a function of the above parameters and its moment of inertia if the particle is a...

We advance a quantitative description of the critical shear rate γ̇c needed to dislodge a spherical particle resting on a surface with a model asperity in laminar and turbulent fluid flows. We have built a cone-plane experimental apparatus which enables measurement of γ̇c over a wide range of particle Reynolds number Rep from 10−3 to 1.5 × 103. The condition to dislodge the particle is found to b...

Differential solar heating can result from shading by rooted emergent aquatic plants, producing a temperature difference between vegetated and unvegetated regions of a surface water body. This temperature difference will promote an exchange flow between the vegetation and open water. Drag associated with the submerged portion of the plants modifies this exchange, specifically, changing the domi...

The inability to monitor wetland drag coefficients at a regional scale is rooted in the difficulty to determine vegetation structure from remote sensing data. Based on the fact that the backscattering coefficient is sensitive to marsh vegetation structure, this paper presents a methodology to estimate the drag coefficient from a combination of SAR images, interaction models and ancillary data. ...

We analyze the dynamic behavior of a spherical microparticle submerged in a fluid medium, driven to the node of a standing bulk acoustic wave created by two opposing transducers. We derive the dynamics of the fluid-particle system taking into account the acoustic radiation force and the time-dependent and time-independent drag force acting on the particle. Using this dynamic model, we character...

This paper theoretically and experimentally investigates the exchange flow due to temperature differences between open water and a canopy of aquatic plants. A numerical model is used to study the interfacial shape, frontal velocity and total volumetric exchange, and their dependence on a dimensionless vegetation drag parameter. The numerical predictions are consistent with the laboratory measur...

We obtain an explicit generalization, within Fokker-Planck dynamics, of Einstein's relation between drag, diffusion, and the equilibrium distribution for a spatially homogeneous system, considering both the transverse and longitudinal diffusion for dimension n>1. We provide a complete characterization of the equilibrium distribution in terms of the drag and diffusion transport coefficients. We ...