The problem of Rayleigh–Bénard’s natural convection subjected to a temporally periodic cooling condition is solved numerically by the Lattice Boltzmann method with multiple relaxation time (LBM-MRT). study finds its interest in field thermal comfort where current knowledge has gaps fundamental phenomena requiring their exploration. Boussinesq approximation considered resolution physical studied...

We perform a two-dimensional numerical study on the thermal effect of porous media global heat transport and flow structure in Rayleigh–Bénard (RB) convection, focusing role conductivity $\lambda$ media, which ranges from $0.1$ to $50$ relative fluid. The simulation is carried out square RB cell with Rayleigh number $Ra$ ranging $10^7$ $10^9$ Prandtl $Pr$ fixed at $4.3$ . porosity system $\phi ...

The first consistent phenomenological theory for two- and three-dimensional Rayleigh-Taylor (RT) turbulence has recently been presented by Chertkov [Phys. Rev. Lett. 91, 115001 (2003)]. By means of direct numerical simulations, we confirm the spatiotemporal prediction of the theory in two dimensions and explore the breakdown of the phenomenological description due to intermittency effects. We s...

Turbulent motions in the interior of a star play an important role in its evolution, since they transport chemical species, thermal energy and angular momentum. Our overall goal is to construct a practical turbulent closure model for convective transport that can be used in a multidimensional stellar evolution calculation including the effects of rotation, shear and magnetic fields. Here, we fo...

The effect of the magnetic field dependent (MFD) viscosity on the thermal convection in a ferromagnetic fluid in the presence of a uniform vertical magnetic field is considered for a fluid layer in a porous medium, heated from below. For a ferromagnetic fluid layer between two free boundaries an exact solution is obtained, using a linear stability analysis. For the case of stationary convection...

We report experimental measurements of heat transport in rotating Rayleigh-Bénard convection in a cylindrical convection cell with an aspect ratio of Γ=1/2. The fluid is helium gas with a Prandtl number Pr=0.7. The range of control parameters for Rayleigh numbers 4×10^{9}<Ra<4×10^{11} and for Ekman numbers 2×10^{-7}<Ek<3×10^{-5} (corresponding to Taylor numbers 4×10^{9}<Ta<1×10^{14} and convect...

‎In this paper‎, ‎we have investigated the chaotic behavior of thermal convection in couple stress liquid saturated porous layer subject to gravity‎, ‎heated from below and cooled from above‎, ‎based on theory of dynamical system‎. ‎A low dimensional Lorenz‎- ‎like model is obtained by using Galerkin-truncation approximation‎. ‎We found that there is proportional relation between scaled couple ...

Consideration is given to small Atwood number (non-dimensional density difference) experiments to investigate mixing driven by Rayleigh-Taylor (R-T) instability. The past 20 years have seen the development of novel experiments to investigate R-T mixing and, simultaneously, the advent of high-fidelity diagnostics. Indeed, the developments of experiments and diagnostics have gone hand in hand, an...

Broad theoretical arguments are proposed to show, formally, that the magnitude G of the temperature gradients in turbulent thermal convection at high Rayleigh numbers obeys the same advection-diffusion equation that governs the temperature fluctuation T , except that the velocity field in the new equation is substantially smoothed. This smoothed field leads to a -1 scaling of the spectrum of G ...