QFS2016 Book of Abstracts

Abstracts

O3.4 Lagrange trajectory of small particles in super fluid HeII Wataru Kubo and Yoshiyuki Tsuji Nagoya University, Department of Energy Engineering and Science, Nagoya city Japan 464-8603 Small tracer parties in HeII are visualized and their motions are analyzed. The particles are made of solid hydrogen whose diameter is an order of micron. In a counter flow, changing the heat flux and bath temperature, Lagrange velocity and accelerations are computed by analyzing the visualized images through PTV technique. We studied how the particle sizes affect the statistics of particle motions. The probability density functions of acceleration shows nearly stretched exponential shape. But the tail part is significantly affected by the particle sizes. These are similar characteristics in classical turbulence. We compared the detail of them and discuss their property. O3.5 Inhomogeneous quantum turbulence in a channel Makoto Tsubota, Satoshi Yui, Shinichi Ikawa Department of Physics, Osaka City University, Osaka 558-8585, Japan We discuss the numerical simulation of inhomogeneous quantum turbulence in a square channel. The recent visualization experiments revealed inhomogeneous flow profile in a channel. We discuss three topics. One is inhomogeneous structure and dynamics of vortices in thermal counterflow[1]. The second is superfluid boundary layer in pure normal flow, where we found the logarithmic velocity profile of superfluid velocity [2]. The last is coflow turbulence. The simulation finds a novel behavior that vortices are dragged into an attractor by the mutual friction [3]. [1] S. Yui, M. Tsubota, Phys. Rev. B91, 174504(2015). [2] S. Yui, K. Fujimoto, M. Tsubota, Phys. Rev. B92, 224513(2015). [3] S. Ikawa, M. Tsubota, Phys. Rev. B93, 184508 (2016).

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