The standard equilibrium for radiation-dominated accretion disks has long been known to be viscously, thermally, and convectively unstable, but the nonlinear development of these instabilities—hence the actual state of such disks—has not yet been identified. By performing local two-dimensional hydrodynamic simulations of disks, we demonstrate that convective motions can release heat sufficientl...

Hgl -,Cd,Te and Cdl -,Zn,Te single crystals were grown by the travelling heater method (THM), applying two different techniques of artificially stirring the solution zone. Accelerated crucible rotation (ACRT) was used in a vertical growth arrangement and compared a technique with constant rotation around the horizontal axis of the ampoule. The dominant hydrodynamic mechanisms of both methods ar...

A finite element model has been used in order to study the mixing process of species in a 100-microm-wide zigzag microchannel integrating a "Y" inlet junction. The distribution of the concentration was obtained by solving successively the Navier-Stokes equation and the diffusion-convection equation in the steady state form. Because of the large range of Reynolds numbers studied (1 < Re < 800), ...

Evaporation of a pure liquid into a inert gas is studied theoretically and experimentally. In contrast with the case where the gas phase is made of pure vapor, the thermocapillary (Marangoni) effect strongly destabilizes the system, and results in intensive and often chaotic forms of interfacial convection. Theoretically, a generalized one-sided model is proposed, which allows to solve thermo-h...

Advection-dominated accretion flows (ADAFs) are known to be convectively unstable for low values of the viscosity parameter α. Two-dimensional axisymmetric hydrodynamic simulations of such flows reveal a radial density profile which is significantly flatter than the ρ ∝ r−3/2 expected for a canonical ADAF. The modified density profile is the result of inward transport of angular momentum by axi...

The present study focused on the investigation of the effects of roughness elements on heat transfer during natural convection in a rectangular cavity using numerical technique. Roughness elements were introduced on the bottom hot wall with a normalized amplitude (A*/H) of 0.1. Thermal and hydrodynamic behaviors were studied using computational method based on Lattice Boltzmann method (LBM). Nu...

Solute transport in fractured rocks is of major interest in many applications: geothermal energy production, petroleum industry, ground water management. This work focuses on a dispersion experiment performed with a transparent replica of a real fracture. The local aperture map was extracted using the well-known Beer-Lambert law, which shows a very heterogeneous medium. The hydrodynamic apertur...

In the hydrodynamic description of ferronematics there are various dynamic magnetic-field effects, linear in the field strength, that are negligible in usual nematics, but can play a role in ferronematics. Here, we investigate theoretically the influence of these new terms on the thermal convection (Rayleigh-Bénard) and the viscous fingering (Saffman-Taylor) instability in ferronematics in the ...

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 ...

The first full-scale three-dimensional core-collapse supernova (SN) simulations with sophisticated neutrino transport show pronounced effects of the standing accretion shock instability (SASI) for two high-mass progenitors (20 and 27 M([Symbol: see text])). In a low-mass progenitor (11.2 M([Symbol: see text])), large-scale convection is the dominant nonradial hydrodynamic instability in the pos...