With the assumption that the bed shear stress fluctuates in a lognormal fashion, the probability density function (pdf) of the standardised bed shear stress is derived as a function of the relative shear stress intensity. The pdf is more skewed with larger relative intensities, but approaches a Gaussian function when the relative intensity is small. The computed pdf agrees well with the reporte...

Present study examines turbulent structures of a rough bed open-channel flow in the context of deterministic approach. Instantaneous velocity field is measured in different hydraulic conditions using two dimensional Particle Image Velocimetry (PIV) in vertical plane and Stereoscopic PIV in horizontal plane. Different techniques and quantities such as swirl strength, two-point and cross-correlat...

[1] Hydrodynamic exchange between a stream and its bed plays an important role in solute transport in rivers. Stream-subsurface exchange is known to occur due to several different mechanisms and different approaches have been used to model the resulting solute transport, but there has been little investigation of the ability of the various models to represent specific exchange processes. This w...

The long-term goal of our research is to improve our understanding of ripple morphodynamics in wave-current, boundary-layer flows. Our main focus is on the study of sediment transport in oscillatory boundary layers in the presence of unidirectional currents and the associated bed morphology (i.e. 2D and 3D ripples). To this end, both wave-induced and wave-current-induced oscillatory flow condit...

Observations of the interactions of large amplitude internal seiches with the sloping boundary of Lake Simcoe, Canada show a pronounced asymmetry between up- and downwelling. Data were obtained during a 42-day period in late summer with an ADCP and an array of four thermistor chains located in a 5 km line at the depths where the thermocline intersects the shallow slope of the lakebed. The therm...

Traditional bed shear stress-based models (e.g., Rouse model) derived from the classic parabolic profile of eddy viscosity in open-channel flows fail to accurately predict suspended sediment concentration (SSC) with aquatic vegetation. We developed a two-layer, turbulence-based model SSC profiles emergent vegetated flows. Turbulence generated vegetation, bed, and coherent structures caused by s...

— We present a wavelet multigrid preconditioner for the conjugale gradient method which gives an efficient solver for the linear System art s ing from a wavelet-Galerkin discretiz.ation of a Dirichlet boundary-value problem via a pénalty/fictitious domain formulation. The preconditioner is chosen to be a wavelet-based multigrid method for solving the same elliptic équation, however over the fic...

Purpose: The fundamental aim of this research was to determine the biomechanical characteristics of the medical bed made of carbon steel and an assessment of its stability. To define the biomechanical characteristics of the bed design, the finite element method (FEM) was applied. Additionally, the risk analysis was conducted according to the directives of ISO 14971 standard. Design/methodology/...

In the computational fluid dynamics (CFD) modeling of gas-solids two phase flow, the effect of boundary conditions play an important role in predicting the hydrodynamic characteristics of fluidized beds. In this work, the hydrodynamics of conical fluidized bed containing dried TiO2 nano-agglomerates were studied both experimentally and computationally. The pressure drop ...