The dynamical origin of the spectral and autocorrelation structure of annular variability in the troposphere is investigated by a deductive approach. Specifically, the structure of the power spectrum and autocorrelation function of the zonal-mean geopotential is analyzed for the case of a quasigeostrophic spherical atmosphere subject to a white noise mechanical forcing applied in a single Hough...

We study the fluid flow at the interface between elastic solids with randomly rough surfaces. We derive (approximate) analytical expressions for the fluid flow factors which enter in the equation describing the fluid flow, and for the frictional shear stress factors which enter in the equation for the frictional shear stress. Numerical results for a rubber cylinder with surface roughness slidin...

I Research on fundamentals for multiphase pipelining ................................................... 1 II Accomplishments of our previous DOE/DE-FG02-87ER 13798, 9/1/98--8/31/01...... 2 III Lubricated transport of viscous oils. Friction factor efficiency ratio......................... 5 IV Numerical simulation of laminar wavy core flow...........................................................

Flow boiling of water across a bank of circular staggered micro-pin fins, 250 lm long and 100 lm diameter with pitch-to-diameter ratio of 1.5, was experimentally studied for mass fluxes ranging from 346 kg/m s to 794 kg/m s and surface heat fluxes ranging from 20 W/cm to 350 W/cm. Local temperature measurements were used to elucidate the two-phase heat transfer coefficients. The flow was visual...

BACKGROUND We hypothesized that longitudinal pulmonary arterial deformation during the cardiac cycle reflects pulmonary arterial capacitance. To examine this hypothesis, we assessed whether tissue Doppler-derived pulmonary annular motion could serve as a novel way to evaluate pulmonary arterial capacitance in pediatric patients with ventricular septal defect (VSD). METHODS In this prospective...

Fluid pulsations can significantly influence behavior of bearings or sealing parts hydraulic machines and therefore their operation. In this contribution, an analytical approach to solve pressure dynamics is compared with a computational solution using acoustic simulation in ANSYS Mechanical FEM package. Studied problem simplified annular gap the are excited either from one annulus end excitati...

Shear thickening in dense particulate suspensions was recently proposed to be driven by the activation of friction above an onset stress needed to overcome repulsive forces between particles. Testing this scenario represents a major challenge because classical rheological approaches do not provide access to the frictional properties of suspensions. Here we adopt a different strategy inspired by...

Frictional and frictionless granular materials in a split-bottom ring shear cell geometry show wide shear bands under slow, quasi-static deformation. Here, the differences between frictional and frictionless materials are elaborated using discrete element simulations (DEM). Several continuum fields like the density, the velocity field, the deformation gradient and the stress are used here for c...