On the Dynamical Buoyancy of Vortices
Abstract
In this paper we consider the effect of dynamical buoyancy (Parker) on the motion of stratified fluid vortex tubes. We find that the dynamical buoyancy force does not necessarily lead to a buoyant rise if there exists a flow field external to a tube. In particular, the vortex tubes presented in our previous work are shown to have a pressure force exactly canceling the buoyancy force so that they do not move vertically (i.e., parallel to gravity) at all. Moreover, we construct a more general class of vortex tubes and find that their vertical motion can be either up or down, depending on the detailed vorticity distribution, regardless of the fact that they are all dynamically buoyant. We find that the vertical motion is intimately related to the horizontal selfmotion of stratified fluid vortex tubes. Finally, we note that the presence of dynamical buoyancy implies that steady state compressible flow solutions for isolated fluid regions in a gravitational field do not exist. These results may have relevance to astrophysical convection.
 Publication:

The Astrophysical Journal
 Pub Date:
 August 1993
 DOI:
 10.1086/172952
 Bibcode:
 1993ApJ...412..664A
 Keywords:

 Buoyancy;
 Compressible Flow;
 Stratified Flow;
 Vortices;
 Stellar Convection;
 Velocity Distribution;
 Fluid Mechanics and Heat Transfer;
 CONVECTION;
 HYDRODYNAMICS