This paper describes the use of particle tracking velocimetry to analyze the Lagrangian acceleration of small particles in superfluid helium with varying time increments, . The probability density of acceleration exhibits Gaussian properties for ,？but displays a lognormal distribution for ,？where is the migration time characterizing the particle motion. The particle trajectories are well characterized by the Hurst exponent H. For smaller time scales than , the trajectories exhibit linear motion (), but have certain fractal properties with for time scales larger than
References
[1]
Landau, L. (1941) Theory of the Superfluidity of Helium II. Physical Review, 60, 356-358. https://doi.org/10.1103/PhysRev.60.356
[2]
Paoletti, M.S., Florlto, R.B., Sreenivasan, K.R. and Lathrop, D.P.J. (2008) Visualization of Superfluid Helium Flow. Journal of the Physical Society of Japan, 77, Article ID: 111007. https://doi.org/10.1143/JPSJ.77.111007
[3]
Bewley, G.P., Lathrop, D.P. and Sreenivasan, K.R. (2006) Visualization of Quantized Vortices. Nature, 441, Article No. 588. https://doi.org/10.1038/441588a
[4]
Murakami, M., Takakoshi, T., Maeda, M., Tsukahara, R. and Yokota, N. (2009) Application of Particle Image Velocimetry for Measuring He II Thermal Counterflow Jets. Cryogenics, 49, 543-548. https://doi.org/10.1016/j.cryogenics.2008.10.020
[5]
Chagovets, T.V. and Sciver, S.W. (2011) A Study of Thermal Counterflow Using Particle Tracking Velocimetry. Physics of Fluids, 23, Article ID: 107102.
https://doi.org/10.1063/1.3657084
[6]
La Mantia, M. and Skrbek, L. (2014) Quantum Turbulence Visualized by Particle Dynamics, Physical Review B, 90, Article ID: 014519.
https://doi.org/10.1103/PhysRevB.90.014519
[7]
Mastracci, B. and Guo, W. (2018) Exploration of Thermal Counterflow in He II Using Particle Tracking Velocimetry. Physical Review Fluids, 3, Article ID: 063304.
https://doi.org/10.1103/PhysRevFluids.3.063304
[8]
Sakaki, N., Maruyama, T. and Tsuji, Y. (2022) Statistics of the Lagrangian Trajectories’ Curvature in Thermal counterflow. Journal of Low Temperature Physics, in press. https://doi.org/10.1007/s10909-022-02674-3
[9]
Kubo, W. and Tsuji, Y. (2019) Statistical Properties of Small Particle Trajectories in a Fully Developed Turbulent State in He-II. Journal of Low Temperature Physics, 196, 170-176. https://doi.org/10.1007/s10909-019-02192-9
[10]
Chen, L., Maruyama, T. and Tsuji, Y. (2022) Statistical Property of Lagrangian Trajectory of Small Particles in Super Fluid He4. Journal of Low Temperature Physics, in press. https://doi.org/10.1007/s10909-022-02691-2
![\"\"](\"Edit_1febe78b-f3b5-4dea-88c6-cad8ac41de21.png\")
![\"\"](\"Edit_fdf82e03-596c-4f17-ba12-c2bfbc191a48.png\")
![\"\"](\"Edit_746c131f-2bdd-4709-a301-923caa9e8f40.png\")
![\"\"](\"Edit_1db25d2c-7572-4b20-8973-88d460aaf6fc.png\")
![\"\"](\"Edit_438151b4-f9b2-4121-aab5-02f2702e81c6.png\")
![\"\"](\"Edit_7cfe244b-9b74-43e6-945b-ec33c770cc16.png\")
![\"\"](\"Edit_17dac2ef-690d-4387-984e-cce749cae4fd.png\")
