What question did this study set out to answer?

To measure the torques associated with the angular acceleration and retardation of superfluid liquid helium II and determine the mechanisms underlying rotational resistance.

December 12, 1957Philosophical Transactions of the Royal Society of London Series A Mathematical and Physical Sciences

The angular acceleration of liquid helium II

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Authors

HHH. E. HallUniversity of Manchester

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Implication

Experimental study reveals asymmetric acceleration and retardation torques in rotating liquid helium II, indicating that superfluid turbulence and vortex lines govern rotational flow.

Key Points

To measure the torques associated with the angular acceleration and retardation of superfluid liquid helium II and determine the mechanisms underlying rotational resistance.
Directly measured torques required to accelerate and retard liquid helium II contained within closely spaced disks at a temperature of 1.27 K.
Assessed the effects of disk surface roughness and flow history on superfluid acceleration dynamics.
Observed an asymmetry between acceleration and retardation processes, with flow remaining macroscopically irrotational during retardation and acceleration forces increasing markedly when disk surfaces were roughened.
Determined that steady-flow mutual friction above a critical velocity aligns with a modified Gorter-Mellink law where A = 23 ± 2 poise⁻¹ and v₀ = -0.6 ± 0.2 cm s⁻¹.
Detected persistent superfluid currents with lifetimes of at least 25 minutes below the critical velocity.

Cite This Study

H. E. Hall (1957) studied this question.

synapsesocial.com/papers/6a854dadf0d179eaafb54f7b https://doi.org/10.1098/rsta.1957.0024

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Implication

Experimental study reveals asymmetric acceleration and retardation torques in rotating liquid helium II, indicating that superfluid turbulence and vortex lines govern rotational flow.

The angular acceleration of liquid helium II

Discussion

Member takes

Implication

Key Points

Cite This Study

The angular acceleration of liquid helium II

Discussion

Member takes

Implication

Key Points

Cite This Study

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