A new mean-field theory of turbulent convection is developed by considering only the small-scale part of spectra as "turbulence" and the large-scale part, as a "mean flow," which includes both regular and semiorganized motions. The developed theory predicts the convective wind instability in a shear-free turbulent convection. This instability causes formation of large-scale semiorganized fluid ...

We present first realistic numerical simulations of 3D radiative convection in the surface layers of main sequence A-type stars with T eff = 8000 K and 8500 K, log g = 4.4 and 4.0, recently performed with the CO 5 BOLD radiation hydrodynamics code. The resulting models are used to investigate the structure of the H+He I and the He II convection zones in comparison with the predictions of local ...

The initial bifurcations in rotating Rayleigh-Bénard convection are studied in the range of dimensionless rotation rate 0 < Ω < 2150 for an aspect-ratio-2.5 cylindrical cell. We used simultaneous optical shadowgraph, heat transport and local temperature measurements to determine the stability and characteristics of the azimuthally-periodic wall convection state. We also show that the second tra...

Convection driven by thermal buoyancy in rotating spherical bodies of fluid has long been recognized as a fundamental process in the understanding of the properties of planets and stars. Since these objects are rotating in general and since their evolution is associated with the transport of heat from their interiors convection influenced by the Coriolis force does indeed play a dominant role i...

Convection-enhanced drug delivery (CED) is a novel approach to directly deliver drugs into brain tissue and brain tumors. It is based on delivering a continuous infusion of drugs via intracranial catheters, enabling convective distribution of high drug concentrations over large volumes of the target tissue while avoiding systemic toxicity. Efficient formation of convection depends on various ph...

In this work, we investigate the effect of air convection on laser-beam pointing noise essential for the long trace profiler (LTP). We describe this pointing error with noise power density (NPD) frequency distributions. It is shown that the NPD spectra due to air convection have a very characteristic form. In the range of frequencies from ~0.05 Hz to ~0.5 Hz, the spectra can be modeled with an ...

We present a discussion on the effects of convection on the uvby colours of A and F stars. The mixing-length theory used in ATLAS9 is compared to the turbulent convection theory of Canuto & Mazzitelli (1991, 1992). Comparison with fundamental stars reveals that colours calculated using the Canuto & Mazzitelli convection theory are generally in better agreement than those obtained using mixing-l...

Deep moist convection plays a crucial role in transporting energy and momentum in the Earth’s atmosphere. Examining the convection is fundamentally important for better understanding of various atmospheric phenomena, e.g., typhoons, as well as the convection itself. We developed a simple methodology for detecting the lifecycle of convection from discrete spatiotemporal data such as output of mo...

The onset of thermal convection in a horizontal layer of a colloidal suspension is investigated in terms of a continuum model for binary-fluid mixtures where the viscosity depends on the local concentration of colloidal particles. With an increasing difference between the viscosity at the warmer and the colder boundary the threshold of convection is reduced in the range of positive values of th...

This work studies the mixed convection heat transfer from a vertical plate in bidisperse porous media with constant wall temperature. The two-velocity two-temperature model is used to derive the governing equations. The effects of the mixed convection parameter, the inter-phase heat transfer parameter, the modified thermal conductivity ratio, and the permeability ratio on the heat transfer and ...