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Volumn 70, Issue 5 2, 2004, Pages

Experimental investigation of the macroscopic flow of he II due to an oscillating grid in the zero temperature limit

Author keywords

[No Author keywords available]

Indexed keywords

CAPACITANCE; COMPUTATIONAL METHODS; DAMPING; DRAG; HYDRODYNAMICS; LAMINAR FLOW; NATURAL FREQUENCIES; OSCILLATIONS; PERMITTIVITY; REYNOLDS NUMBER; VISCOSITY; VORTEX FLOW;

EID: 41349114380     PISSN: 15393755     EISSN: None     Source Type: Journal    
DOI: 10.1103/PhysRevE.70.056307     Document Type: Article
Times cited : (48)

References (51)
  • 24
    • 11844250219 scopus 로고    scopus 로고
    • note
    • -9 exerted a measurable effect on the creation rate.
  • 28
    • 11844297612 scopus 로고    scopus 로고
    • note
    • We have checked the reduction factor by adding extra lengths of coaxial cable of known capacitance.
  • 29
    • 11844252876 scopus 로고    scopus 로고
    • note
    • This statement is valid for the fundamental mode of vibration; clearly, it does not hold if higher modes become excited.
  • 30
    • 11844276269 scopus 로고    scopus 로고
    • note
    • While driving the grid hard in He II, additional oscillation modes can be excited and observed. At modest drive levels, however, their resonant amplitude is more than two orders of magnitude lower than that of the fundamental and they appear as small but clearly observable glitches on both sides of the resonance peak.
  • 31
    • 11844282411 scopus 로고    scopus 로고
    • note
    • In our preliminary report [22] we have overestimated the grid velocity by a factor of 4, due to an error in derivation of Eq. (2).
  • 32
    • 11844277297 scopus 로고    scopus 로고
    • note
    • We cannot exclude that while driving the grid in vacuum at a high amplitude its temperature rises, as the thermal link to the cell is extremely weak. This can cause changes in elastic behavior of the oscillating grid.
  • 34
    • 11844250839 scopus 로고    scopus 로고
    • private communication
    • A. M. Guénault (private communication).
    • Guénault, A.M.1
  • 38
    • 11844306876 scopus 로고    scopus 로고
    • note
    • By neglecting the radial displacement profile in approximating the grid motion as one dimensional, one underestimates the peak velocity at its geometrical center by a factor ≃ 2.3, as discussed later.
  • 39
    • 0004168443 scopus 로고
    • Cambridge University Press, Cam- bridge, U.K.
    • H. Lamb, Hydrodynamics (Cambridge University Press, Cam-bridge, U.K., 1932).
    • (1932) Hydrodynamics
    • Lamb, H.1
  • 43
    • 11844286559 scopus 로고    scopus 로고
    • note
    • Note that a similar effect could be accounted for through an increase in the damping constant, assuming it to be imaginary. The resulting shift would have a different frequency dependence, linear in ω rather than quadratic. Unfortunately, within the narrow accessible range of ω, we cannot distinguish between the two dependences.
  • 51
    • 11844258492 scopus 로고    scopus 로고
    • note
    • Given the rough surface of the grid, the nucleation centers are probably more or less randomly distributed over its whole area. Simple analysis then shows that the highest probability of reaching a threshold is along a circle of r≈0.4R and thus close to the node circle if the grid were to oscillate in the axisymmetric (0,2) mode.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.