In the last decades it has been recognized that the very high Rayleigh number convective boundary layer (CBL) has more complex nature than might be reckoned. Besides the fully organized component naturally considered as the mean flow and the chaotic small-scale turbulent fluctuations, one more type of motion has been discovered, namely, long-lived large-scale structures, which are neither turbu...

The qualitative effect of nonuniform temperature gradient on the linear stability analysis of the Rayleigh-Benard convection problem in a Boussinesquian, viscoelastic fluid-filled, high-porosity medium is studied numerically using the single-term Galerkin technique. The eigenvalue is obtained for free-free, free-rigid, and rigid-rigid boundary combinations with isothermal temperature conditions...

In recent experiments on the initial stages of pattern formation in a Rayleigh Benard convection cell, Meyer e t al. I1) observed very irregular patterns. In these experiments, the fluid was subjected to a heat current that varied either linearly or periodically in time from below to above the onset of the first instability. If the side wall of the cylindrical cell was made of a material with a...

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...