scholarly journals Thermo-convection in a polytropic atmosphere.

1955 ◽  
Vol 60 ◽  
pp. 179
Author(s):  
Andrew Skumanich
Keyword(s):  
Polytropic Atmosphere

scholarly journals Oscillatory convection in strong magnetic fields and origin of active regions

1968 ◽  
Vol 35 ◽  
pp. 127-130 ◽  
Author(s):  
S. I. Syrovatsky ◽  
Y. D. Zhugzhda
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Active Regions ◽  
Oscillatory Convection ◽  
Strong Magnetic Fields ◽  
Various Boundary Conditions ◽  
Convective Cells ◽  
The Magnetic Field ◽  
Polytropic Atmosphere

The convection in a compressible inhomogeneous conducting fluid in the presence of a vertical uniform magnetic field has been studied. It is shown that a new mode of oscillatory convection occurs, which exists in arbitrarily strong magnetic fields. The convective cells are stretched along the magnetic field, their horizontal dimensions are determined by radiative cooling. Criteria for convective instability in a polytropic atmosphere are obtained for various boundary conditions in the case when the Alfvén velocity is higher compared with the velocity of sound.The role of oscillatory convection in the origin of sunspots and active regions is discussed.

On vortex air motions above an axisymmetric source of mass, momentum and heat

1995 ◽  
Vol 290 ◽  
pp. 299-317
Author(s):  
Y. A. Berezin ◽  
K. Hutter
Keyword(s):  
Large Scale ◽  
Nonlinear Differential Equations ◽  
Azimuthal Velocity ◽  
Small Scale ◽  
Ambient Atmosphere ◽  
Plume Dispersion ◽  
Governing Equations ◽  
Balance Equations ◽  
Velocity Pressure ◽  
Polytropic Atmosphere

We study axisymmetric plume dispersion from a steady source of mass, momentum and/or heat that is subjected to either a time-dependent large-scale external vortex or small-scale turbulent axisymmetric helicity. On the basis of the turbulent boundary layer and Boussinesq assumptions and by assuming similarity profiles with Gaussian distribution in the radial direction the balance equations of mass, momentum, and energy reduce to a system of nonlinear differential equations for amplitude functions of axial velocity, pressure and density differences as well as azimuthal velocity. The system of equations is closed with Taylor's entrainment assumption.The plume radius and the typical radius of the large-scale external vortex are also determined. For a simple density structure of the ambient atmosphere (i.e. adiabatic conditions) analytical results can be obtained, but for more complicated cases, i.e. a layered polytropic atmosphere, the governing equations are examined numerically; computations are reasonably simple and efficient.

Convective column above a linear fire in a polytropic atmosphere

1978 ◽  
Vol 14 (3) ◽  
pp. 271-275 ◽  
Author(s):  
Yu. A. Gostintsev ◽  
L. A. Sukhanov
Keyword(s):  
Convective Column ◽  
Polytropic Atmosphere

scholarly journals Nonlinear instability of baroclinic atmosphere with reference to planetary scale disturbances

2004 ◽  
Vol 11 (3) ◽  
pp. 363-370
Author(s):  
I. A. Pisnichenko
Keyword(s):  
Zonal Wind ◽  
Sufficient Conditions ◽  
Zonal Flow ◽  
Vertical Gradient ◽  
Finite Amplitude ◽  
Lapse Rate ◽  
Temperature Lapse Rate ◽  
Planetary Scale ◽  
Conditions Of Stability ◽  
Polytropic Atmosphere

Abstract. In this paper we investigate the stability of zonal flow in a baroclinic atmosphere with respect to finite-amplitude planetary-scale disturbances by applying Arnold's method. Specifically, we examine the sign of the second variation of a conserved functional for the case of a polytropic atmosphere (i.e. one with a linear lapse rate) and with a linear profile of zonal wind. Sufficient stability conditions for an infinite atmosphere (i.e. with a temperature lapse rate equal to zero) are satisfied only for an atmosphere in solid body rotation. For a polytropic atmosphere of finite extent (a lapse rate is not equal zero) the sufficient conditions of stability can be satisfied if a lid is placed below min (Zmax, polytropic atmospheric height). The dependence of height Zmax on values of the vertical gradient of the zonal wind and the zonal temperature distribution is calculated.

Overstabilization of acoustic modes in a polytropic atmosphere

Solar Physics ◽  
1978 ◽  
Vol 56 (2) ◽  
Author(s):  
H.M. Antia ◽  
S.M. Chitre ◽  
D.M. Kale
Keyword(s):  
Acoustic Modes ◽  
Polytropic Atmosphere

scholarly journals Magnetic flux concentrations in a polytropic atmosphere

2014 ◽  
Vol 564 ◽  
pp. A2 ◽  
Author(s):  
I. R. Losada ◽  
A. Brandenburg ◽  
N. Kleeorin ◽  
I. Rogachevskii
Keyword(s):  
Magnetic Flux ◽  
Polytropic Atmosphere
Sign in / Sign up

Export Citation Format

Share Document