The modified log-wake law, which was developed for turbulent boundary layers and pipe flows, is extended to turbulent flows in open-channels. Turbulent velocity profiles in open-channels can be approximated with three components: (1) the law of the wall that results from the constant bed shear stress; (2) the law of the wake that reflects the effects of gravity, secondary currents and bed rough...

Fluid shear stress alters the morphology and function of the endothelium by activating several kinases. Furthermore, shear stress potently inhibits apoptosis of endothelial cells. Since activation of Akt kinase has been shown to prevent cell death, we investigated the effects of shear stress on Akt phosphorylation. To test the hypothesis that shear stress interacts with the Akt kinase pathway, ...

A tidal bore impacts significantly on the estuarine ecosystem, although little is known on the flow field, mixing and sediment motion beneath tidal bores. In the absence of detailed systematic field measurements, a quasi-steady flow analogy was applied to investigate undular tidal bores with inflow Froude numbers between 1.25 and 1.6. Experimental results indicated that rapid flow redistributio...

In this paper we derive a new morphological model, with an extended version of the sediment transport model for mean step length (the average distance travelled by particles), in which depends on bed shear stress. This makes increase increasing flow, line previous experimental results. To account suspension and large-scale turbulent structures rivers, also explicitly water depth. approach enabl...

A linear stability analysis of sediment transport by wind or water over an erodible bed shows that perturbations in a narrow range of wavenumbers are ampli ed, leading to the formation of ripples with a wavelength dependent on the roughness length of the bed. The roughness length is proportional to the grain size of the sand and the square of the excess shear velocity at the bed. We propose tha...

[1] Data on channel geometry in naturally incising bedrock rivers reveal variable relationships between channel width, slope, and erosion rate. To explain the range of relationships between these parameters, we propose an optimized channel geometry model. The model reproduces previous theoretical and numerical modeling scaling relationships; however, to explain the field data, the model must in...

Using inverse methods constrained by recent satellite observations, we have produced a comprehensive estimate of the basal shear stress beneath the Filchner-Ronne ice streams. The inversions indicate that a weak bed (approx. 4-20kPa) underlies much of these ice streams. Compared to the Ross ice streams, the distribution of weak subglacial till is more heterogeneous, with 'sticky spots' providin...

BACKGROUND Atherosclerotic lesions are predominantly observed in curved arteries and near side branches, where low or oscillatory shear stress patterns occur, suggesting a causal connection. However, the effect of shear stress on plaque vulnerability is unknown because the lack of an appropriate in vivo model precludes cause-effect studies. METHODS AND RESULTS We developed a perivascular shea...