Knudsen-to-Hydrodynamic Crossover in Liquid 3He in a High-Porosity Aerogel
Other Condensed Matter
2012-06-05 v2 Fluid Dynamics
Abstract
We present a combined experimental and theoretical study of the drag force acting on a high porosity aerogel immersed in liquid He and its effect on sound propagation. The drag force is characterized by the Knudsen number, which is defined as the ratio of the quasiparticle mean free path to the radius of an aerogel strand. Evidence of the Knudsen-hydrodynamic crossover is clearly demonstrated by a drastic change in the temperature dependence of ultrasound attenuation in 98% porosity aerogel. Our theoretical analysis shows that the frictional sound damping caused by the drag force is governed by distinct laws in the two regimes, providing excellent agreement with the experimental observation.
Keywords
Cite
@article{arxiv.1201.5259,
title = {Knudsen-to-Hydrodynamic Crossover in Liquid 3He in a High-Porosity Aerogel},
author = {H. Takeuchi and S. Higashitani and K. Nagai and H. C. Choi and B. H. Moon and N. Masuhara and M. W. Meisel and Y. Lee and N. Mulders},
journal= {arXiv preprint arXiv:1201.5259},
year = {2012}
}
Comments
5 pages, 3 figures