The present study describes entrainment characteristics of bed material into debris flow, based on flume tests, numerical and dimensional analyses. Flume tests are conducted to investigate influences of bed sediment size on erosion rate by supplying debris flows having unsaturated sediment concentration over erodible beds. Experimental results show that the erosion rate decreases monotonically ...

We perform numerical simulations of a shear flow over a periodically patterned substrate with entrapped gas bubbles. A diffuse-interface model is employed to handle the liquid-gas interface deformation and the three-phase contact line. Depending on the shear rate and the pattern geometry, four flow regimes are observed. The contact lines can be pinned, depinned, or eliminated depending on the c...

Turbidity currents in the ocean and lakes are driven by suspended sediment. The vertical profiles of velocity and excess density are shaped by interaction between the current and bed as well as between the current and the ambient water. This paper presents 48 series of experiments in which saline gravity currents flow through a laboratory sinuous flume. flume contains three successive bends wit...

Nucleation is an out-of-equilibrium process that can be strongly affected by the presence of external fields. In this paper, we report a simple extension of classical nucleation theory to systems submitted to an homogeneous shear flow. The theory involves accounting for the anisotropy of the critical nucleus formation and introduces a shear-rate-dependent effective temperature. This extended th...

The effect of shear on the rupture of two stratified thin liquid films confined between parallel plates and subject to van der Waals forces is examined in this work. Lubrication theory is applied to derive a one-dimensional nonlinear evolution equation for the height of the liquid-liquid interface. Linear stability analysis reveals that the real part of the growth rate and the wavelength of the...

The esti mati on of the functions that descri be the shear stress and the pressure drop across the short orifice die as a function of shear rate at different mean pressures for linear-low-density polyethylene copolymer (LLDPE) at 190oC is obtained using Genetic Programmi ng (GP) . The GP has been running base d on e xpe rimental data in two cases; shear stress and pressure drop at differe nt me...

OBJECTIVE The objective of this study is to delineate the molecular mechanisms responsible for Staphylococcus aureus-platelet adhesion as a function of physiologically relevant wall shear stresses. METHODS AND RESULTS A parallel plate flow chamber was used to quantify adhesion of wild-type, Spa-, ClfA- and SdrCDE- strains to immobilized platelet layers. In the absence of plasma, adhesion incr...

Molecular dynamics simulations are used to investigate the influence of molecular-scale surface roughness on the slip behavior in thin liquid films. The slip length increases almost linearly with the shear rate for atomically smooth rigid walls and incommensurate structures of the liquid/solid interface. The thermal fluctuations of the wall atoms lead to an effective surface roughness, which ma...

he microstructure of dense suspensions of anisotropic particles that are ordered at rest is explored nder shear as a function of particle anisotropy and shear rate using small angle neutron scattering. or suspensions containing spheres and mildly anisotropic heteronuclear dicolloids, after reshearing, long-range order is present in the form of randomly stacked hexagonally close packed ayers. As...

Flow recirculation zones and shear rate are associated with distinct pathogenic biological pathways relevant to thrombosis and atherogenesis. The interaction between stenosis severity and lesion eccentricity in determining the length of flow recirculation zones and peak shear rate in human coronary arteries in vivo is unclear. Computational fluid dynamic simulations were performed under resting...