8 research outputs found
Bubble Growth in Superfluid 3-He: The Dynamics of the Curved A-B Interface
We study the hydrodynamics of the A-B interface with finite curvature. The
interface tension is shown to enhance both the transition velocity and the
amplitudes of second sound. In addition, the magnetic signals emitted by the
growing bubble are calculated, and the interaction between many growing bubbles
is considered.Comment: 20 pages, 3 figures, LaTeX, ITP-UH 11/9
Dissipation of the 3^He A-B Transition
A rigorous hydrodynamic theory of the A-B transition is presented. All
dissipative processes are considered. At low interface velocities, those
occurring on hydrodynamic length scales, not considered hitherto, are most
probably the dominant ones.Comment: 13 pages, REVTeX, 2 figures, ITP-UH 13/9
Why hyperbolic theories of dissipation cannot be ignored: Comments on a paper by Kostadt and Liu
Contrary to what is asserted in a recent paper by Kostadt and Liu ("Causality
and stability of the relativistic diffusion equation"), experiments can tell
apart (and in fact do) hyperbolic theories from parabolic theories of
dissipation. It is stressed that the existence of a non--negligible relaxation
time does not imply for the system to be out of the hydrodynamic regime.Comment: 8 pages Latex, to appear in Phys.Rev.
Granular Solid Hydrodynamics
Granular elasticity, an elasticity theory useful for calculating static
stress distribution in granular media, is generalized to the dynamic case by
including the plastic contribution of the strain. A complete hydrodynamic
theory is derived based on the hypothesis that granular medium turns
transiently elastic when deformed. This theory includes both the true and the
granular temperatures, and employs a free energy expression that encapsulates a
full jamming phase diagram, in the space spanned by pressure, shear stress,
density and granular temperature. For the special case of stationary granular
temperatures, the derived hydrodynamic theory reduces to {\em hypoplasticity},
a state-of-the-art engineering model.Comment: 42 pages 3 fi