Attenuation of the fourth sound in liquid helium II via extended thermodynamics

Mongiovı̀, Maria Stella; Peruzza, R.A.

doi:10.1016/s0020-7462(03)00092-1

Cited by 7 publications

(2 citation statements)

References 23 publications

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“…This leads to us to think that in the superfluid helium intrinsic dissipative phenomena are present, which are responsible for the attenuation of fourth sound. In a further work we will study in detail this problem [42].…”

Section: Discussionmentioning

confidence: 99%

“…Using the data reported by Maynard, taking into account the expressions (2.1.8) and (2.1.9), we determine the values of V 2 1 and V 2 2 as solutions of equation: .17) can be regarded as a system of four equations in the four unknowns λ 0 , λ 2 , β and β . However, at least to our knowledge, the experimental data on fourth sound attenuation do not allow a sufficiently accurate determination of k (4) s because, when helium II flows inside a porous medium, other attenuation mechanisms are active, such as heat exchanges with the powder grains, beside the attenuation due to the internal dissipative phenomena of helium II [42]. For this reason we will perform our comparison with experimental data under the simplified hypothesis β = β .…”

Section: Velocity Of the IV Sound In A Superleakmentioning

confidence: 99%

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Velocity of the fourth sound in liquid helium II via extended thermodynamics

Mongiovı̀

Peruzza

2003

Zeitschrift f�r Angewandte Mathematik und Physik (ZAMP)

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This work continues a study begun in previous works, where, using Extended Thermodynamics, a monofluid model of liquid helium II is formulated. The wave propagation in bulk liquid helium II is studied in the hypothesis that the thermal dilatation is not zero. The propagation of fourth sound, studied previously neglecting both the thermal dilatation and finite volume of the powder, is studied without these simplified hypotheses: a scattering correction n is introduced to take into account the porosity. The model is more general than the standard two-fluid model because it allows that a small amount of entropy is associated with helium when it flows through a very thin capillary or a porous medium. A comparison with experimental data is performed. From experimental values for velocities and attenuations of the two sounds in bulk liquid helium, the model provides the velocity of fourth sound in a porous medium. These values are determined at various temperatures and pressures and compared with fourth sound measurements in a packed powder. Mathematics Subject Classification (2000). 82 D 50 , 80 A 20 , 76 S 05 .

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Section: Discussionmentioning

confidence: 99%

Section: Velocity Of the IV Sound In A Superleakmentioning

confidence: 99%

Velocity of the fourth sound in liquid helium II via extended thermodynamics

Mongiovı̀

Peruzza

2003

Zeitschrift f�r Angewandte Mathematik und Physik (ZAMP)

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Wave propagation in anisotropic turbulent superfluids

Ardizzone

Gaeta

Mongiovı̀

2013

Z. Angew. Math. Phys.

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In this work, a hydrodynamical model of Superfluid Turbulence previously formulated is applied to study how the presence of a non-isotropic turbulent vortex tangle modifies the propagation of waves. Two cases are considered: wave front parallel and orthogonal to the heat flux. Using a perturbation method, the first-order corrections due to the presence of the vortex tangle to the speeds and to the amplitudes of the first and second sound are determined. It is seen that the presence of the quantized vortices couples first and second sound, and the attenuation of second sound is proportional to the line density L if the wave propagates orthogonal to the heat flux, while it is proportional to the square root of L if the wave propagates parallel with the heat flux

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Effects of heat flux on λ-transition in liquid 4He

Mongiovı̀

Saluto

2014

Meccanica

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Attenuation of the fourth sound in liquid helium II via extended thermodynamics

Cited by 7 publications

References 23 publications

Velocity of the fourth sound in liquid helium II via extended thermodynamics

Velocity of the fourth sound in liquid helium II via extended thermodynamics

Wave propagation in anisotropic turbulent superfluids

Effects of heat flux on λ-transition in liquid 4He

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