A theoretical approach proposed by Elperin et al. Phys. Rev. E 66, 066305 2002 is developed further to investigate formation of large-scale coherent structures in a nonrotating turbulent convection via excitation of a large-scale instability. In particular, the convective-wind instability that causes formation of large-scale coherent motions in the form of cells, can be excited in a shear-free ...

The hydrodynamic and thermal lattice Boltzmann methods are applied to investigate the turbulent convective heat transfer in the wavy channel flows. In this study, the turbulent phenomena are modeling by large-eddy simulations with the Smagorinsky model. As a benchmark, the laminar and turbulent backward-facing step flows are simulated first. The results give good agreement with other numerical ...

Heat and mass convection ............................................................................................................................. 1 Heat convection: what it is ........................................................................................................................ 1 Types of heat convection .......................................................................

In this study, the flow-field and forced-convection characteristics of turbulent flow through plates with streamwise periodic ribs is simulated by a faster converged numerical method. The method based on self-adjusted under relaxation factors is motivated from the concept of Bi-CGSTAB algorithm, which updates the solution vectors by the 2-norm minimization of the residual vectors of the governi...

Convection in a fluid heated from below, known as Rayleigh-Bénard convection, is an important turbulent process that occurs in the sun, planetary atmospheres, industrial manufacturing, and many other places. Physicists and engineers have made much progress in understanding this phenomenon in simple laboratory geometries, but still have a way to go before they are able to extrapolate to the extr...

Turbulent convection is often present in liquids with a kinematic viscosity much smaller than the diffusivity of the temperature. Here we reveal why these convection flows obey a much stronger level of fluid turbulence than those in which kinematic viscosity and thermal diffusivity are the same; i.e., the Prandtl number Pr is unity. We compare turbulent convection in air at Pr=0.7 and in liquid...

We investigate the utility of the convex hull ofmany Lagrangian tracers to analyze transport properties of turbulent flowswith different anisotropy. In direct numerical simulations of statistically homogeneous and stationaryNavier–Stokes turbulence, neutral fluid Boussinesq convection, and MHDBoussinesq convection a comparisonwith Lagrangian pair dispersion shows that convex hull statistics cap...