The main purpose of this paper is to compare the predictions of four laws currently used for the estimation of the wall shear stress in an incompressible turbulent boundary layer-viz., A proposal is also made for a modified skin-friction law which would appear to predict values of the wall shear stress to within about 5 percent over its range of validity. A feature of this new law is that close...

The strength and ductility of nanolayered materials are determined by a delicate balance between dislocation and interface motion under applied mechanical loading. We present here studies of dislocation and interface motion in single crystal and nanotwinned copper, utilizing molecular dynamics simulations. Motion of twin boundary interfaces themselves is dictated by the stress state at the inte...

The main objective of this study was to numerically assess the effect of boundary elements with different types of steel and concrete materials on nonlinear behavior of composite steel–reinforced concrete wall (CSRCW) by employing ABAQUS software. Two types of common steel profiles including box and I-shaped sections, located at the middle and extremities of the wall, were employed to assess th...

The stress field at the tip of a crack of a thin plate of elastic material that is broken due to a mode III shear tearing has a universal form with a nonuniversal amplitude, known as the stress intensity factor, which depends on the crack length and the boundary conditions. We present in this paper exact analytic results for this stress intensity factor, thus enriching the small number of exact...

1. Filamentous algae are widespread in freshwater ecosystems worldwide with a significant presence in streams, rivers and lakes with sufficient light and nutrients. Although typically not a preferred food source for grazers, dense filamentous mats provide surfaces for epiphytic microorganisms that are more palatable, thus adding to stream productivity. 2. We tested the hypothesis that epiphytes...

Recently, Mathis et al. (2011) developed a conceptual approach that is able to predict instantaneous wall-shear stress fluctuations in turbulent boundary layers. This approach embeds the scale interaction mechanisms, namely superposition and modulation, into a wall-model capable of predicting the fluctuating component of the streamwise wall-shear stress. The present study investigates the poten...

Accurate predictions of the sea state–dependent air–sea momentum flux require a thorough understanding of the wave boundary layer turbulence over surface waves. A set of momentum and energy equations is derived to formulate and analyze wave boundary layer turbulence. The equations are written in wavefollowing coordinates, and all variables are decomposed into horizontalmean, wave fluctuation, a...