The Simulation of Dispersion by Convective Turbulence in the Atmosphere

1987 ◽  
pp. 143-149
Author(s):  
F. T. M. Nieuwstadt ◽  
J. P. J. M. M. de Valk
Keyword(s):  
Convective Turbulence

scholarly journals Study of the Dynamics of Convective Turbulence in the Solar Granulation by Spectral Line Broadening and Asymmetry

2020 ◽  
Vol 890 (2) ◽  
pp. 138 ◽  
Author(s):  
Ryohtaroh T. Ishikawa ◽  
Yukio Katsukawa ◽  
Takayoshi Oba ◽  
Motoki Nakata ◽  
Kenichi Nagaoka ◽  
...  
Keyword(s):  
Spectral Line ◽  
Line Broadening ◽  
Solar Granulation ◽  
Convective Turbulence ◽  
Spectral Line Broadening

DECAY OF CONVECTIVE TURBULENCE REVISITED

1997 ◽  
Vol 82 (3) ◽  
pp. 503-517 ◽  
Author(s):  
Zbigniew Sorbjan
Keyword(s):  
Convective Turbulence

scholarly journals Anisotropic particles in two-dimensional convective turbulence

2020 ◽  
Vol 32 (2) ◽  
pp. 023305 ◽  
Author(s):  
Enrico Calzavarini
Keyword(s):  
Two Dimensional ◽  
Anisotropic Particles ◽  
Convective Turbulence

Long-wave decay due to convective turbulence

1976 ◽  
Vol 73 (3) ◽  
pp. 427-444 ◽  
Author(s):  
Theodore Green ◽  
See Whan Kang
Keyword(s):  
Simple Model ◽  
Rayleigh Number ◽  
Reynolds Stress ◽  
Decay Estimate ◽  
Oscillating Flow ◽  
Convective Turbulence ◽  
Decay Component ◽  
Wave Decay ◽  
Long Wave ◽  
Rectangular Basin

Long waves are generated in a laboratory-size rectangular basin, which is heated uniformly from below. Their subsequent decay is measured, and the decay component due to the action of convective turbulence isolated, using a combination of existing theories and interpretation techniques. An expression is proposed for the turbulent decay decrement as a function of the bulk Rayleigh number. The results agree as well as can be expected with a simple model based on a Reynolds-stress decay estimate obtained by superposing convective thermals on the oscillating flow associated with the long wave.

scholarly journals The Origin of the Enhanced Dissipation “α” in Accretion Discs and its Relation to Gamma Bursts

1987 ◽  
Vol 125 ◽  
pp. 546-546
Author(s):  
Stirling A. Colgate
Keyword(s):  
Neutron Star ◽  
Energy Release ◽  
Velocity Shear ◽  
Accretion Discs ◽  
Large Energy ◽  
Necessary Condition ◽  
Large Temperature ◽  
Fluid Viscosity ◽  
Convective Turbulence ◽  
Gamma Burst

The source of the enhanced dissipation or “α” viscosity of Keplerian accretion discs is central in all putative mechanisms for large energy release by matter accreting onto condensed objects and for the basic mechanism of star formation. The circumstances of gamma burst formation on neutron stars suggest convective buoyancy as a necessary condition for the large α. This is because the total mass ≅ 1019 g necessary to supply the energy of a gamma burst derived from infall is a natural limit for the mass stored in a disc without α viscosity. This suggests that buoyancy driven convective turbulence is the source of the enhanced transport in disc evolution models (Shakura and Sunyaev 1973). In support of this conjecture we find that the maximum possible energy released by ideal friction operating on the velocity shear of a disc is twice that required to destabilize the angular momentum distribution of such a disc. The heat energy available from an α viscosity is twice that necessary to create α in the first place. Hence, a nonlinear instability–nonlinear to create convective turbulence and nonlinear to create shear viscosity heating–is sufficient to drive α. One characteristic that would prevent the formation of such an instability is degeneracy of the disc matter as it accumulates near a neutron star (Paczynski and Jaroszynski 1978). Degeneracy inhibits strong convection because a given energy release within degenerate matter results in a large temperature, and hence large energy transport without convection. Convection occurs in an accretion disc whenever the energy which is dissipated in the disc requires a superadiabatic temperature gradient for its radiative or conductive transport to the surface. Some gamma burst mechanisms require exactly such a mechanism as a degenerate disc close to the neutron star in the correct mass (≅ 1019 g), at the correct radius several times the neutron star radius, to supply gravitational energy for a gamma burst. The degenerate disc accumulates mass stably until the density is great enough that degenerate fluid viscosity evolves the disc into contact with the neutron star. The large energy released by velocity shear at contact heats the disc causing rapid evolution and a gamma burst.

scholarly journals On Magnetic Mixing and Rotation in Stellar Evolution

1978 ◽  
Vol 80 ◽  
pp. 323-331
Author(s):  
Peter G. Gross
Keyword(s):  
Magnetic Fields ◽  
Stellar Evolution ◽  
Evolutionary Status ◽  
Relevant Parameter ◽  
Stellar Rotation ◽  
Convective Turbulence ◽  
Stellar Interior ◽  
Magnetic Mixing ◽  
Ap Stars

In this paper some thoughts and problems are presented from the viewpoint that the evolution of stars may play a key role in generating magnetic fields which, in turn, may affect the mixing of nuclearly processed elements from the stellar interior to the surface. The relevant parameter is stellar rotation which, upon interaction with convective turbulence driven by thermal instabilities, leads to the generation of magnetic fields. A possible connection to Bidelman's hypothesis on the evolutionary status of Ap stars is also discussed in the context of a post-core-helium-flash hypothesis.

Impurity driven current-convective turbulence in the SOL plasma

1996 ◽  
Vol 36 (2-3) ◽  
pp. 197-201 ◽  
Author(s):  
A. V. Nedospasov
Keyword(s):  
Convective Turbulence

Route to non-Gaussian statistics in convective turbulence

2007 ◽  
Vol 75 (3) ◽  
Author(s):  
Roberto Festa ◽  
Andrea Mazzino ◽  
Marco Tizzi
Keyword(s):  
Convective Turbulence ◽  
Gaussian Statistics ◽  
Non Gaussian
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