A numerical study of the onset of convection in rotating, internally heated, selfgravitating fluid spheres is presented. The exploration of the stability of the conduction state versus the Taylor and the Prandtl numbers supplies a detailed idea of the laws that fulfil the four types of solutions obtained at low Prandtl numbers. The main result found is that axisymmetric (torsional) modes of con...

Bounds for the bulk heat transport in Rayleigh-Benard convection for an infinite Prandtl number fluid are derived from the primitive equations. The enhancement of heat transport beyond the minimal conduction value (the Nusselt number Nu) is bounded in terms of the nondimensional temperature difference across the layer (the Rayleigh number Ra) according to Nu ≤ c Ra where c < 1 is an absolute co...

Motivated by the roll-switching behavior observed in rotating Rayleigh-Benard convection, we define a Küppers-Lortz (K-L) state as a volume-preserving flow with periodic roll switching. For an individual roll state, the Lagrangian particle trajectories are periodic. In a system with roll-switching, the particles can exhibit three-dimensional, chaotic motion. We study a simple phenomenological m...

We consider surface-tension driven convection in a rotating fluid layer. For nearly insulating boundary conditions we derive a long-wave equation for the convection planform. Using a Galerkin method and direct numerical simulations we study the stability of the steady hexagonal patterns with respect to general side band instabilities. In the presence of rotation, steady and oscillatory instabil...

We present numerical dynamo models which qualitatively reproduce some structural characteristics of the present-day geomagnetic field. Timedependent convection in an electrically conducting, rotating spherical shell at Ekman numbers 1 3 x l0 -4 generates dipole-dominated magnetic fields, which exhibit distinct bundles of strong radial flux at high latitudes, low flux over the poles, and paired ...

Gravity dependent transport phenomena in various industrial processes are investigated in order to indicate new directions for micro-gravity research that enhance the commercial success of the space program. The present article describes the commercialization possibilities of such topics associated with physicochemical transport phenomena. The topics are: coating flow, rotating electrochemical ...

The behavior of rotating and nonrotating aggregated convection is examined at various horizontal resolutions using the hypohydrostatic, or reduced acceleration in the vertical (RAVE), rescaling. This modification of the equations of motion reduces the scale separation between convectiveand larger-scale motions, enabling the simultaneous and explicit representation of both types of flow in a sin...

Convection in a cylindrical container of small aspect ratio is studied. It is known that when, in addition to buoyancy forces, thermocapillarity effects are taken into account, resonant interactions of two modes may appear. In the case of 1:2 resonance amplitude equations are derived, showing the existence of a stable heteroclinic orbit and rotating waves, until now not observed experimentally.