An endothermic phase change in the presence of chemical heterogeneitles can act as an efficient filter, such that heavy material is sequestered below the phase change and light material is trapped above the phase change. Due to the fact that the endothermlc phase change damps thermal convection, it can act as a "trap door" for chemical heterogeneitles Ascending flows which are chemically dense ...

The convection-radiation effects in thermal fluid flows are studied based on the Lattice Boltzmann method. Nine-velocity flow and temperature distributions are used to obtain the mass, momentum and energy equations in thermal incompressible flows by studying equivalent moment systems. The radiative heat flux in the energy equation is obtained using the discrete-ordinates solution of the radiati...

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 ...

This paper studies the influence of convection by periodic or cellular flows on the effective diffusivity of a passive scalar transported by the fluid when the molecular diffusivity is small. The flows are generated by two-dimensional, steady, divergence-free, periodic velocity fields.

A low diffusion E-CUSP (LDE) scheme for preconditioned Navier-Stokes equations is developed. With unfactored implicit Gauss-Seidel relaxation scheme for time integration, the LDE scheme with high-order WENO reconstruction is used to simulate several flows at various speed from low speed natural convection to supersonic flows. Numerical results are presented to show efficiency, accuracy and robu...

We describe a relatively simple time-dependent convection model that can be coupled to the equations of radiation hydrodynamics. We show that it behaves in a physically plausible way in protostellar collapse flows and is quantitatively correct for nonlinear RR-Lyrae pulsations and the Sun. Together with the equations of radiation hydrodynamics the model closely approximates the classical stella...