Search results for "fourth sound"
showing 2 items of 2 documents
Propagation of fourth sound in turbulent superfluids via extended thermodynamics
2011
The work deals with further developments of a study previously initiated, in which a macroscopic one-fluid model of inhomogeneous turbulent superfluids, based on extended thermodynamics, had been formulated. In this work the study is carried on. First the influence of the remnant vortices on the propagation of the first and second sound is studied. Then a boundary condition able to explain the reversible flow of superfluid flowing through a thin capillary is postulated and two vector fields, which have the dimensions of velocity and can be interpreted as the velocities of normal and superfluid components, are introduced. By using these new fields, a comparison between this model and the Hal…
Flow of turbulent superfluid helium inside a porous medium
2009
The work deals with further developments of a study previously initiated, in which a macroscopic model of inhomogeneous superfluid turbulence, based on extended thermodynamics, has been formulated. The model choose as fundamental fields, beside the traditional fields, two extra variables: the averaged vortex line length per unit volume and the heat flux. Using this model the propagation of the fourth sound inside a superleak is investigated: it is shown that, if the configuration of the vortex tangle inside the superleak are not altered -on the average- by the presence of the walls, when the fourth sound is propagated, vibrations in the vortex line density are present, too.