The onset of double diffusive convection in a viscoelastic fluid-saturated porous layer is studied when the fluid and solid phase are not in local thermal equilibrium. The modified Darcy model is used for the momentum equation and a two-field model is used for energy equation each representing the fluid and solid phases separately. The effect of thermal non-equilibrium on the onset of double di...

Very large eddy simulations of high-aspect-ratio unbounded Rayleigh-Bénard convection for Pr=0.71 over a 10-decade range of Rayleigh numbers (Ra=10(5)-10(15)) reveal a consolidation and dramatic thinning of the wall boundary layer with an increase in the Ra number. The fingerlike plumes between planform structures become also thinner, more distant, but much more vigorous. The Ra exponent in the...

A modeling procedure is developed for natural convection heat transfer from an isothermal heated sphere located at the center of an isothermal, cooled, sphericalshaped enclosure. The model is based on the linear superposition of conduction and convection solutions, where the convective component is determined based on a combination of two limiting cases, laminar boundary layer convection and tr...

The present study focused on the investigation of the effects of roughness elements on heat transfer during natural convection in a rectangular cavity using numerical technique. Roughness elements were introduced on the bottom hot wall with a normalized amplitude (A*/H) of 0.1. Thermal and hydrodynamic behaviors were studied using computational method based on Lattice Boltzmann method (LBM). Nu...

[1] Laboratory and numerical experiments show that when a chemically different layer overlies a hotter but otherwise denser layer, analogous to continental mantle lithosphere over asthenosphere, convective stability depends strongly on both the critical Rayleigh number and the buoyancy number, B, of the lithosphere-like layer. Sufficient cooling at low buoyancy number results in an oscillatory ...

The phenomenon of irregular cessation and subsequent reversal of the large-scale circulation in turbulent Rayleigh-Bénard convection is theoretically analyzed. The force and thermal balance on a single plume detached from the thermal boundary layer yields a set of coupled nonlinear equations, whose dynamics is related to the Lorenz equations. For Prandtl and Rayleigh numbers in the range 10(-2)...

The potential pe~ormance of mobile peer-to-peer frequencyhopping communication systems in multiple-access networks is studied. Through analysis and simulation, the effects of Rayleigh fding, shadowing, spectral splattec the number offiequency channels, spatial diversity, and thermal noise are examined.

Linear stability analysis of double diffusive convection in a horizontal porous layer saturated with fluid is examined by considering the effects of viscous dissipation, concentration based internal heat source and vertical throughflow. The basic steady state solution for Governing equations is derived. Linear stability analysis has been implemented numerically by using shooting and Runge-kutta...

We investigate large Rayleigh number (10– 10) and large Prandtl number (10– 10) thermal convection in glycerol in an aspect ration one cubic cell. The kinematic viscosity of the fluid strongly depends upon the temperature. The symmetry between the top and bottom boundary layers is thus broken, the so-called non-Boussinesq regime. In a previous paper Wu and Libchaber have proposed that in such a...