Predictions of the gas temperature and pressure profiles are vital to the design and operation of gas transmission lines. Available analytical methods for the calculation of these profiles are evaluated and a numerical framework for the rigorous calculation has been developed. The predictions from both the analytical and numerical procedure have been compared to field data from the Iranian Gas ...

[1] In the study of natural rivers, accurate conveyance estimation is challenging because of complex cross-sectional geometry and variable flow resistance. The aim of this study was to investigate the additional friction factor due to lateral momentum transfer at the interface of vegetated and nonvegetated channel parts in two rivers: (1) the Rhine River, a large dredged river with partially ve...

We develop a simplified model to predict the frictional behaviour of the contact between the surfaces of a rotary shouldered thread connection in the make-up process of premium tubular connections as used in the oil pipeline business. A classic wear model is applied at the scale of the surface asperities to predict the evolution of friction between initially shot-peened surface and bronze plate...

The Hasimoto planar vortex filament is one of the rare exact solutions to the classical local induction approximation (LIA). This solution persists in the absence of friction or other disturbances, and it maintains its form over time. As such, the dynamics of such a filament have not been extended to more complicated physical situations. We consider the planar vortex filament under the quantum ...

Related Articles Heat transfer and friction factor of solar air heater having duct roughened artificially with discrete multiple v-ribs J. Renewable Sustainable Energy 4, 033103 (2012) Heat transfer and friction characteristics of dimple-shaped roughness element arranged in angular fashion (arc) on the absorber plate of solar air heater J. Renewable Sustainable Energy 4, 023112 (2012) Experimen...

Viscosity has always been a critical property of lubricants. It is the source of the hydrodynamic lubrication that separates lubricated surfaces moving past one another under pressure and thus is a major factor in reducing wear. On the other hand, viscosity is also a form of friction – viscous friction – and, as it absorbs energy, viscosity reduces the efficiency of the engine even as it protec...

Negative skin friction occurs when concrete piles are situated in soft soils, consolidating soilmass, etc., resulting in a downward force that increases loading on shaft piles and reduces the bearing capacity of the piles. A new concept based on the shifting rate of piles, and the settlement rate of the surrounding soils has been suggested far the study of negative skin friction. Negative skin ...

We investigate shock response of single crystal and nanocrystalline pentaerythritol tetranitrate (PETN) with a coarse-grained model and molecular dynamics simulations, as regards mechanical hotspot formation in the absence or presence of grain boundaries (GBs). Single crystals with different orientations, and columnar nanocrystalline PETN with regular hexagonal, irregular hexagonal, and random ...

This paper analyzes local lattice rotations introduced in severely deformed polycrystalline titanium by friction stir welding. Nondestructive three-dimensional (3D) spatially resolved polychromatic X-ray microdiffraction, is used to resolve the local crystal structure of the restructured surface from neighboring local structures in the sample material. The measurements reveal strong gradients o...

in all engineering applications where solid surfaces slide on each other, friction plays an important role. it becomes even more important, particularly in metal forming processes where the two sliding materials are metallic. among forming processes, forging is an important process, because of improving material structure, mechanical properties and reducing production time. an inverse analysis ...