Search results for "Liquid Helium II."

showing 5 items of 5 documents

Bollettino di Matematica pura e applicata

2020

The paper emphasizes some the advances of knowledge in mathematics problems ad new applications. The Bollettino is open to the contribution of Italian or foreign researchers.

Block designLebesgue improper integralBmPaSettore MAT/05 - Analisi MatematicaBoll. di mat. Pura ed appl.Liquid Helium II.Hadamard designFirst return integralNon Equilibrium Thermodynamic
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Attenuation of the Fourth Sound in Liquid Helium II via Extended Thermodymamics

2004

Extended thermodynamicNon-equilibrium thermodynamicLiquid helium IISuper4uid
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Vortex density waves and high-frequency second sound in superfluid turbulence hydrodynamics

2010

In this paper we show that a recent hydrodynamical model of superfluid turbulence describes vortex density waves and their effects on the speed of high-frequency second sound. In this frequency regime, the vortex dynamics is not purely diffusive, as for low frequencies, but exhibits ondulatory features, whose influence on the second sound is here explored.

PhysicsNon-equilibrium thermodynamicsTurbulenceQuantum vortexFOS: Physical sciencesGeneral Physics and AstronomyNon-equilibrium thermodynamicsVorticityLiquid helium IISuperfluid turbulenceVortexCondensed Matter - Other Condensed MatterSuperfluidityClassical mechanicsSecond soundSettore MAT/07 - Fisica MatematicaSuperfluid helium-4Other Condensed Matter (cond-mat.other)
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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…

PhysicsSuperfluiditygeographygeography.geographical_feature_categorySettore MAT/05 - Analisi MatematicaTurbulenceGeneral Physics and AstronomyThermodynamicsGeneral ChemistryNon Equilibrium Thermodynamics Liquid Helium II Superfluid Turbulence Fourth sound Porous media.Settore MAT/07 - Fisica MatematicaSound (geography)Journal of Non-Equilibrium Thermodynamics
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Hydrodynamic equations of anisotropic, polarized and inhomogeneous superfluid vortex tangles

2008

We include the effects of anisotropy and polarization in the hydrodynamics of inhomogeneous vortex tangles, thus generalizing the well known Hall-Vinen-Bekarevich-Khalatnikov equations, which do not take them in consideration. These effects contribute to the mutual friction force ${\bf F}_{ns}$ between normal and superfluid components and to the vortex tension force $\rho_s{\bf T}$. These equations are complemented by an evolution equation for the vortex line density $L$, which takes into account these contributions. These equations are expected to be more suitable than the usual ones for rotating counterflows, or turbulence behind a cylinder, or turbulence produced by a grid of parallel th…

PhysicsTurbulenceCondensed Matter::OtherFOS: Physical sciencesStatistical and Nonlinear PhysicsTourbillonCondensed Matter PhysicsPolarization (waves)VortexCylinder (engine)law.inventionSuperfluidityPhysics::Fluid DynamicsCondensed Matter - Other Condensed MatterClassical mechanicslawEvolution equationAnisotropySettore MAT/07 - Fisica MatematicaSuperfluid turbulence Liquid helium II Hydrodynamic equationsOther Condensed Matter (cond-mat.other)
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