We present a detailed bifurcation scenario of zero-Prandtl number Rayleigh-Bénard convection using direct numerical simulations (DNS) and a 27-mode low-dimensional model containing the most energetic modes of DNS. The bifurcation analysis reveals a rich variety of convective flow patterns and chaotic solutions, some of which are common to that of the 13-mode model of Pal et al. [EPL 87, 54003 (...

Forced turbulence simulations are used to determine the turbulent kinematic viscosity, νt, from the decay rate of a large scale velocity field. Likewise, the turbulent magnetic diffusivity, ηt, is determined from the decay of a large scale magnetic field. In the kinematic regime, when the field is weak, the turbulent magnetic Prandtl number, νt/ηt, is about unity. When the field is nonhelical, ...

We show that stationary statistical properties for uniformly dissipative dynamical systems are upper semi-continuous under regular perturbation and a special type of singular perturbation in time of relaxation type. The results presented are applicable to many physical systems such as the singular limit of infinite Prandtl-Darcy number in the Darcy-Boussinesq system for convection in porous med...

In numerical Rayleigh-BCnard convection at Rayleigh number lo5 and 5 x 105, Prandtl numbers 0.07, 0.7, and 7, and aspect ratios 3, 4 or 6, large-scale patterns are sought. For aspect ratio 6 and Pr = 0.7, saturation of the mean velocity is only observed after 20 convective timescales. Three-dimensional visualization shows a strong influence of the confining sidewalls and corners for all Prandtl...

In numerical Rayleigh-B enard convection at Rayleigh number 10 5 and 5 10 5 , Prandtl numbers 0.07, 0.7, and 7, and aspect ratios 3, 4 or 6, large-scale patterns are sought. For aspect ratio 6 and P r = 0:7, saturation of the mean velocity is only observed after 20 convective timescales. Three-dimensional visualization shows a strong innuence of the connning sidewalls and corners for all Prandt...

The boundary layer fluid flow in a channel with heat source, soret effects and slip condition was studied. The governing equations were solved using perturbation technique. The effects of different parameters such Prandtl number Pr , Hartmann number M, Schmidt number Sc, suction parameter  , soret number Sr and the heat source s on velocity, temperature and concentration were studied. Numerica...

In this paper, the problem of laminar nanofluid flow which results from the nonlinear stretching of a flat sheet is investigated numerically. In this paper, a modified variable physical properties model for analyzing nanofluids flow and heat transfer is introduced. In this model, the effective viscosity, density, and thermal conductivity of the solid-liquid mixture (nanofluids) which are common...

A problem of flow and heat transfer in a non-Newtonian Maxwell liquid film over an unsteady stretching sheet embedded in a porous medium in the presence of a thermal radiation is investigated. The unsteady boundary layer equations describing the problem are transformed to a system of non-linear ordinary differential equations which is solved numerically using the shooting method. The effects of...