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Experimental investigation of the dynamics of a vibrating grid in superfluid 4He over a range of temperatures pressures.

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Experimental investigation of the dynamics of a vibrating grid in superfluid 4He over a range of temperatures pressures. / Charalambous, D.; Skrbek, L.; Hendry, P. C. et al.
In: Physical Review E, Vol. 74, No. 3, 20.09.2006, p. 036307-03610.

Research output: Contribution to Journal/MagazineJournal articlepeer-review

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Charalambous D, Skrbek L, Hendry PC, McClintock PVE, Vinen WF. Experimental investigation of the dynamics of a vibrating grid in superfluid 4He over a range of temperatures pressures. Physical Review E. 2006 Sept 20;74(3):036307-03610. doi: 10.1103/PhysRevE.74.036307

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Charalambous, D. ; Skrbek, L. ; Hendry, P. C. et al. / Experimental investigation of the dynamics of a vibrating grid in superfluid 4He over a range of temperatures pressures. In: Physical Review E. 2006 ; Vol. 74, No. 3. pp. 036307-03610.

Bibtex

@article{97f09ceabfb74ca89e8ffe5498da8334,
title = "Experimental investigation of the dynamics of a vibrating grid in superfluid 4He over a range of temperatures pressures.",
abstract = "In an earlier paper [Nichol et al., Phys. Rev. E, 70, 056307 (2004)] some of the present authors presented the results of an experimental study of the dynamics of a stretched grid driven into vibration at or near its resonant frequency in isotopically pure superfluid 4He over a range of pressures at a very low temperature, where the density of normal fluid is negligible. In this paper we present the results of a similar study, based on a different grid, but now including the temperature range where the normal fluid density is no longer insignificant. The new grid is very similar to the old one except for a small difference in the character of its surface roughness. In many respects the results at low temperature are similar to those for the old grid. At low amplitudes the results are somewhat history dependent, but in essence there is no damping greater than that in vacuo. At a critical amplitude corresponding to a velocity of about 50 mm s−1 there is a sudden and large increase in damping, which can be attributed to the generation of new vortex lines. Strange shifts in the resonant frequency at intermediate amplitudes observed with the old grid are no longer seen, however they must therefore have been associated with the different surface roughness, or perhaps were due simply to some artifact of the old grid, the details of which we are currently unable to determine. With the new grid we have studied both the damping at low amplitudes due to excitations of the normal fluid, and the dependence of the supercritical damping on temperature. We present evidence that in helium at low amplitudes there may be some enhancement in the effective mass of the grid in addition to that associated with potential flow of the helium. In some circumstances small satellite resonances are seen near the main fundamental grid resonance, which are attributed to coupling to some other oscillatory system within the experimental cell.",
author = "D. Charalambous and L. Skrbek and Hendry, {P. C.} and McClintock, {Peter V. E.} and Vinen, {W. F.}",
year = "2006",
month = sep,
day = "20",
doi = "10.1103/PhysRevE.74.036307",
language = "English",
volume = "74",
pages = "036307--03610",
journal = "Physical Review E",
issn = "1539-3755",
publisher = "American Physical Society",
number = "3",

}

RIS

TY - JOUR

T1 - Experimental investigation of the dynamics of a vibrating grid in superfluid 4He over a range of temperatures pressures.

AU - Charalambous, D.

AU - Skrbek, L.

AU - Hendry, P. C.

AU - McClintock, Peter V. E.

AU - Vinen, W. F.

PY - 2006/9/20

Y1 - 2006/9/20

N2 - In an earlier paper [Nichol et al., Phys. Rev. E, 70, 056307 (2004)] some of the present authors presented the results of an experimental study of the dynamics of a stretched grid driven into vibration at or near its resonant frequency in isotopically pure superfluid 4He over a range of pressures at a very low temperature, where the density of normal fluid is negligible. In this paper we present the results of a similar study, based on a different grid, but now including the temperature range where the normal fluid density is no longer insignificant. The new grid is very similar to the old one except for a small difference in the character of its surface roughness. In many respects the results at low temperature are similar to those for the old grid. At low amplitudes the results are somewhat history dependent, but in essence there is no damping greater than that in vacuo. At a critical amplitude corresponding to a velocity of about 50 mm s−1 there is a sudden and large increase in damping, which can be attributed to the generation of new vortex lines. Strange shifts in the resonant frequency at intermediate amplitudes observed with the old grid are no longer seen, however they must therefore have been associated with the different surface roughness, or perhaps were due simply to some artifact of the old grid, the details of which we are currently unable to determine. With the new grid we have studied both the damping at low amplitudes due to excitations of the normal fluid, and the dependence of the supercritical damping on temperature. We present evidence that in helium at low amplitudes there may be some enhancement in the effective mass of the grid in addition to that associated with potential flow of the helium. In some circumstances small satellite resonances are seen near the main fundamental grid resonance, which are attributed to coupling to some other oscillatory system within the experimental cell.

AB - In an earlier paper [Nichol et al., Phys. Rev. E, 70, 056307 (2004)] some of the present authors presented the results of an experimental study of the dynamics of a stretched grid driven into vibration at or near its resonant frequency in isotopically pure superfluid 4He over a range of pressures at a very low temperature, where the density of normal fluid is negligible. In this paper we present the results of a similar study, based on a different grid, but now including the temperature range where the normal fluid density is no longer insignificant. The new grid is very similar to the old one except for a small difference in the character of its surface roughness. In many respects the results at low temperature are similar to those for the old grid. At low amplitudes the results are somewhat history dependent, but in essence there is no damping greater than that in vacuo. At a critical amplitude corresponding to a velocity of about 50 mm s−1 there is a sudden and large increase in damping, which can be attributed to the generation of new vortex lines. Strange shifts in the resonant frequency at intermediate amplitudes observed with the old grid are no longer seen, however they must therefore have been associated with the different surface roughness, or perhaps were due simply to some artifact of the old grid, the details of which we are currently unable to determine. With the new grid we have studied both the damping at low amplitudes due to excitations of the normal fluid, and the dependence of the supercritical damping on temperature. We present evidence that in helium at low amplitudes there may be some enhancement in the effective mass of the grid in addition to that associated with potential flow of the helium. In some circumstances small satellite resonances are seen near the main fundamental grid resonance, which are attributed to coupling to some other oscillatory system within the experimental cell.

U2 - 10.1103/PhysRevE.74.036307

DO - 10.1103/PhysRevE.74.036307

M3 - Journal article

VL - 74

SP - 36307

EP - 33610

JO - Physical Review E

JF - Physical Review E

SN - 1539-3755

IS - 3

ER -