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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Experimental investigation of the macroscopic flow of He II due to an oscillating grid in the zero temperature limit
AU - Nichol, H. A.
AU - Skrbek, L.
AU - Hendry, P. C.
AU - McClintock, P. V.E.
PY - 2004/1/1
Y1 - 2004/1/1
N2 - A systematic experimental investigation of the macroscopic flow properties of extremely pure He II in the zero temperature limit is reported, covering the pressure range [Formula presented]. The flow is generated by electrostatically driven oscillations of a thin, tightly stretched, circular, square-mesh nickel grid. With growing amplitude of oscillation, the flow changes character at a first critical threshold from pure inviscid superflow past a submerged body of hydrodynamically enhanced mass, to a flow regime that is believed to involve a boundary layer composed of quantized vortex loops. Here the oscillatory motion of the grid acquires strongly nonlinear features. These include double-valued (reentrant) resonance curves and a decrease in the resonant frequency with increasing drive amplitude, but without any appreciable increase in damping. On further increase of the drive level, a second critical threshold is attained: here, the resonant frequency reaches a stable value, the response amplitude almost stops growing, but the linewidth increases. Finally, the flow acquires the character of fully developed classical turbulence, characterized by a square-root dependence of flow velocity on the driving force. Additional flow features attributable to the presence of remanent vorticity are observed and discussed.
AB - A systematic experimental investigation of the macroscopic flow properties of extremely pure He II in the zero temperature limit is reported, covering the pressure range [Formula presented]. The flow is generated by electrostatically driven oscillations of a thin, tightly stretched, circular, square-mesh nickel grid. With growing amplitude of oscillation, the flow changes character at a first critical threshold from pure inviscid superflow past a submerged body of hydrodynamically enhanced mass, to a flow regime that is believed to involve a boundary layer composed of quantized vortex loops. Here the oscillatory motion of the grid acquires strongly nonlinear features. These include double-valued (reentrant) resonance curves and a decrease in the resonant frequency with increasing drive amplitude, but without any appreciable increase in damping. On further increase of the drive level, a second critical threshold is attained: here, the resonant frequency reaches a stable value, the response amplitude almost stops growing, but the linewidth increases. Finally, the flow acquires the character of fully developed classical turbulence, characterized by a square-root dependence of flow velocity on the driving force. Additional flow features attributable to the presence of remanent vorticity are observed and discussed.
U2 - 10.1103/PhysRevE.70.056307
DO - 10.1103/PhysRevE.70.056307
M3 - Journal article
AN - SCOPUS:85036255419
VL - 70
JO - Physical Review E - Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics
JF - Physical Review E - Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics
SN - 1063-651X
IS - 5
M1 - 056307
ER -