ISSN:
1573-7357
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract We have studied nonlinear dissipation in oscillatory flow of3He-A through 49-µm- and 17-µm-wide channels by means of torsion pendulum experiments at about 50 Hz. The observed effects are strongly history dependent; the dissipation at a given measuring amplitude is strongly increased if the sample is cooled through Tc while oscillating at large amplitude. Once a highly dissipative state has been created it does not noticeably decay below Tc, though a more dissipative state can be created below Tc by a period of sufficiently large-amplitude oscillation. The results are described semiquantitatively by a model based on the idea of superflow collapse by motion of the $$\hat l$$ vector, with consequent orbital dissipation. The history dependence is introduced into this model by postulating the existence of surface singularities in the $$\hat l$$ texture, the density of which is determined by the previous history of the helium.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00683553
